Find top content marketing agencies to craft engaging brand stories that drive tangible business outcomes. Select experts from our vetted list of content marketing companies that specialize in copywriting, social media, and SEO.
After carefully considering each agency’s client reviews, pricing, range of content marketing services, portfolios, and industry reputation, we handpicked the finest content marketing companies. Below, you’ll discover what sets each of these agencies apart, as well as our ranking criteria.
The Number 1 Content Marketing Agency as Selected by DesignRush Is:
Notable Clients: Warner Brothers, eBay, Caliber Collision, and more
HigherVisibility produces content marketing that drives profitable business growth through its proprietary Targeted Growth System (TGS). Its steps involve custom strategy development, precise audience targeting, data-driven execution, and continuous optimization. With it, the content marketing company has helped clients increase organic leads by 191% and achieved a 124% return on ad spend. Moreover, it has won multiple awards and recognitions, including the Search Engine Land Awards and the US Agency Awards.
Despite its established reputation, Allied Van Lines fell behind competitors. It struggled with low-quality content, leading to lower site authority, poor search visibility, reduced organic traffic and lead generation, and disavowed quality links.
To resolve these issues, it partnered with HigherVisibility. The content marketing agency used historic data to identify valuable keywords, develop relevant and engaging content, optimize on-page elements, and implement link building and conversion rate optimization (CRO) tactics. As a result, Allied Van Lines increased year-on-year (YoY) organic traffic by 2.6%, month-on-month (MoM) leads by 800%, and YoY organic conversions by 9.4%.
Notable Clients: Nextiva, Casper, TripAdvisor, Norton, Airbnb, and more
Siege Media offers a unique approach to enhancing your website's authority through passive link building. As a collective of creatives, marketers, and SEO experts, Siege Media has generated content valued at approximately $12,387,175 per month in client traffic, which equates to $148,646,100 per year.
Zendesk approached Siege Media with the realization that its outdated content failed to generate desired traffic levels. It needed experts who could implement SEO best practices, conduct comprehensive keyword research, and create high-quality and strategic content to enhance its search engine ranking, drive traffic growth, and increase conversions.
The agency then revamped Zendesk’s existing content, focusing on technical SEO and design optimization. It also implemented a bottom-funnel strategy on their blog and service pages, featuring content that showcased the client’s expertise in software, customer service, and technology. These content pieces effectively combined informational and transactional elements and utilized high-quality imagery and user-friendly charts. The result was a surge in traffic: 37% growth to Zendesk’s blog, $731,924 in overall traffic value growth, 94% growth in organic traffic, and 10,675+ passive links.
Notable Clients: Miner, Stanford University, Rubbermaid Commercial, Canva, Cisco Systems, and more
Brafton's mission is to help businesses succeed through content marketing services and technology solutions worldwide. Its creative and consulting teams write for any industry, from technically complex niches to B2B and B2C brands, utilizing data-led digital content to resonate with the audience and generate results.
The strategy for their client, Quench USA, was to increase brand awareness by enhancing the company’s presence on search. With this in mind, Brafton crafted an SEO strategy that targeted not just consumers but also executives, small-business owners, and office administrators. Using a mix of general terms, such as “hydration facts,” and commercial-intent terms, like “water cooler service for office,” the agency ensured that the website ranked on Page 1 for the right keywords. Consequently, Quench achieved 37 new Page 1 keywords, with 21 being in positions 1 to 5, a $55,377 boost in monthly traffic value, and an increase of 443% in monthly traffic.
Notable Clients: Adobe, Amazon, Asana, Dropbox, eBay, Facebook, Fiverr, and more
Since its establishment in 2009, Column Five has been a leading creative agency specializing in B2B ventures. The agency harnesses the incredible power of storytelling as the ultimate differentiator, transforming ideas into successful campaigns for Fortune 500 companies, startups, and SMEs. It empowers brands to connect with their lifelong customers, foster meaningful relationships, and make conscious decisions that benefit individuals, profitability, and our shared planet.
Dropbox wanted to enhance its Talent Brand by introducing its brand to potential employees, attracting new talent, and engaging with the community. To provide an honest and genuine glimpse into #LifeInsideDropbox, Column Five created a series of videos featuring employees from around the world sharing their career journeys at Dropbox. This series aimed to humanize the brand, generate enthusiasm, and inspire viewers by recounting an authentic view of life within the organization.
Notable Clients: Twenty 20, Nextiva, Harris Teeter, Intuit, and more
Single Grain is a team of passionate professionals who use cutting-edge tools and technology, and personalized marketing strategies to generate leads, drive sales, and foster genuine connections. The agency’s remote-first approach allows them to work with talented creatives regardless of location.
One of their clients, Intuit, a well-known name in tax and personal finance services, recognized an opportunity to provide easy-to-use tools for other business aspects, such as website creation. While Intuit developed and launched the Intuit Website Builder, it needed help to gain traction and visibility in a new and different marketplace dominated by more established competitors. To tackle this challenge, it enlisted the services of Single Grain to create high-quality content and solidify its reputation as a powerful website-building solution.
The firm conducted an in-depth competitive analysis and increased efforts in blogging and social media to engage the existing user community and connect with new users. Within only seven months, the collaboration significantly increased Intuit's visibility in a highly competitive keyword environment across a wide range of common search terms.
Notable Clients: Sodexo, Adobe, Cisco, Salesforce, Autodesk, and more
Tendo is a comprehensive B2B content agency with expertise in crafting, implementing, and optimizing integrated content experiences that drive toward ambitious business objectives. It is a collective of seasoned strategists and creative minds with the knack for transforming a distinctive value proposition into a captivating narrative that resonates with the client’s key audiences.
When the existing Cisco.com needed to revamp its outdated content, Tendo conducted in-depth research to develop a content framework that could be expanded and maintained easily throughout the site. After evaluating the site’s current state, reviewing competitors, and interviewing key stakeholders, they created a content architecture and scalable content models, including organization, prioritization, and copy specifications for key page types.
Following this redesign, unique visitors to Cisco.com increased by 15%, task completion rose by 13%, and the click-through rate skyrocketed to 68%. Additionally, "contact us" clicks saw a remarkable 32% increase. The success was further validated through metrics, prompting Cisco to develop a design system based on Tendo’s content framework and apply it across all business units.
Notable Clients: Semrush, BigCommerce, SpyFu, Sprout Social, Influencer Marketing Hubb, and more
Attrock is a results-driven digital marketing company with an impressive track record of helping clients achieve remarkable milestones, including ranking for over 5,000 keywords on Google's first page and driving a 128% increase in leads and conversions.
It also played a vital role in scaling agencies from five to seven-figure incomes within two years by providing digital marketing services like content marketing, SEO, influencer Marketing, PR, lead Generation, and more.
Its content marketing campaign for ShaneBarker.com was aimed at increasing backlinks, building a strong social media presence, improving SERPs rankings, and boosting site traffic. By optimizing the web content and implementing SEO measures, its blog posts started to rank on the first page of Google search results without the need for link building. High-quality social media content also helped nurture its robust social media presence, with the number of sessions from LinkedIn growing from 686 to 16,000 in two years.
Notable Clients: Las Vegas Tourism, Miami Beach Pride, Midmark, BurgerFi, and more
S&G is a renowned content marketing agency consisting of experienced experts with diverse backgrounds, from prestigious newspapers, renowned magazines, Fortune 500 companies, and innovative technology firms. Its expertise has earned them recognition, making it among the top 50 global content marketing agencies by The Content Marketing Institute.
S&G collaborated with JW Aluminum to position the brand as a disruptor in the traditional metals manufacturing industry; it launched a new app to reduce lead times for procurement professionals and streamline supply chains for customers.
The firm created a comprehensive white paper exploring supply chain logistics in the metals industry and how technology could improve efficiency and boost revenue. The white paper generated over 200 new leads in only six months and served as a landing page for JWA's PR campaign, resulting in feature stories in Forbes, Supply Chain Brain, and other relevant industry publications.
Notable Clients: PayPal, NetApp, Sofinnova, and more
The Content Bureau is a fully remote, majority-female team dedicated to ensuring client success by balancing corporate marketing and branding protocols with trusted partnerships to provide maximum value over time. Its specialty is crafting B2B marketing assets, including copywriting, editing, and layout solutions for articles, banner ads, blog posts, and webinars.
The firm produced authentic and unscripted thought leadership videos for their client, SAP, to help partners and marketing staff understand the company's software business model. The challenge was to create engaging and authentic content while adhering to SAP brand guidelines.
According to the client, the collaboration between them and the agency resulted in fun, painless, and on-brand videos. It successfully delivered work quickly and professionally, reaching thousands of viewers and earning positive feedback from field sales representatives. Overall, the authenticity behind the videos proved to be a successful sales tool that effectively communicated the message to their target audience.
Notable Clients: monday.com, Freshworks, ActiveCampaign, AdEspresso, Zapier, and more
Codeless produces hundreds of long-form articles each month for some of the internet's biggest SaaS, service, and affiliate brands. Its process begins with SEO experts identifying content categories that resonate with the target market. The dedicated account managers then facilitate the production process, from keyword identification to uploading the finished product to your CMS.
The agency helped monday.com increase monthly blog traffic from 12,586 to more than 304,000 within 18 months. Despite the hyper-competitive nature of B2B and SaaS niches, Codeless helped them expand its business and secure significant clients such as Coca-Cola, Hulu, and Universal.
Its strategy involved creating content at scale to produce 950+ articles (2,000 words each). This enabled the client to rank for 140,000+ organic keywords with 25,626 first-page rankings on SERPs and amass backlinks from 6,500+ domains, adding to their traffic numbers.
How We Picked the Best Content Marketing Companies
To curate the list of the top content marketing companies, we examined the agencies’ client roster, testimonials, case studies, industry reputation, team expertise, and executive management. Our team of agency experts created a scoring system to gauge their overall performance based on metrics such as:
Relevant content marketing service catalog
Coverage of content marketing topics on their website and other channels
The number of content marketing projects delivered
The quality and diversity of portfolio, and success stories
Notable clients and well-known brands
Their online reputation on DesignRush, Google, and other platforms
This qualitative process helped us narrow down the cream of the crop content marketing providers you can work with on your upcoming project.
10 Most Popular Content Marketing Agencies Compared
Agency Name
Location
Hourly Rate
Size
Best For
HigherVisibility
Memphis, TN
Inquire
50-99
Overall
Siege Media
San Diego, CA
$100
100-249
Conversion-Focused Content
Brafton
Boston, MA
$150
100-249
SEO
Column Five Media
Orange County, CA
$145
Under 49
SaaS Companies
Single Grain
Los Angeles, CA
Inquire
Under 49
B2C Enterprises
Tendo Communications
San Francisco, CA
Inquire
Under 49
B2B Brands
Attrock
Miami, FL
$49
Under 49
Content Analysis
S&G
Miami, FL
$175
Under 49
Branded Content
The Content Bureau
Orinda, FL
Inquire
Under 49
Internal Marketing
Codeless
Lone Tree, CO
Inquire
50-99
Long-Form Content
Best Content Marketing Companies
5,106 Companies-Rankings updated: August 20, 2026
DesignRush assesses content marketing companies for their expertise and verified client experiences to help you make better decisions. Certain agencies have paid placements.
We are a modern, young & creative agency for really good inbound content & PR from Munich. We love what we do for our clients. Not only with heart & soul, but also with the appropriate brains and a lot of expertise around text, image, video and SEO. This is how we produce, distribute and promote really good...
It is your business, but it is our content strategy that will help your business grow.
It is your business, but it is our content strategy that will help your business grow.
We are committed to helping small business owners achieve their goals, by providing services like creating an effective marketing plan and content strategy, as well as imparting knowledge about the latest marketing trends. Additionally, we strive to provide solutions to everyday marketing problems faced by...
The DM Nexa Marketing is a Carmarthen UK-based agency specializing in social media content marketing, advertisement campaign management, search engine optimization, and branding...
Tribeca Public Relations is an award-winning, leading PR agency in South Africa. We are lead by our five TRIBE values of teamwork, relationships, integrity, bravery and excellence. We are passionate about public relations and the impact it has on our clients’ business objectives...
Your Success Partner for Digital Marketing Strategy, Social Media and ECommerce.
Your Success Partner for Digital Marketing Strategy, Social Media and ECommerce.
We accelerate digital marketing success for startups, niche brands, high-growth companies, and industry leaders. Our expertise helps you build a powerful online presence, connect with your ideal audience, and drive measurable results through data-driven strategies and high-converting campaigns...
Roofing SEO services is a specialist roofing agency built exclusively for roofing companies that want consistent rankings, qualified leads, and real revenue growth. We understand the industry, the competition, and the search intent behind every roofing enquiry...
A design agency based in Chicago, IL. Our goal is always to understand our clients' wants and needs, and to use creativity as an edge to help them achieve success. We like to make bold designs. We believe that business doesn't have to be boring. Brands and websites shouldn't feel more like a burden than a...
E-PR onlineis a global platform that makes publishing in top-tier international media accessible to any individual or company. Leverage the agency's professional copywriting, marketing, and PR services to boost your brand's visibility, credibility, and SERP ratings in no time...
Libra Consulting is a boutique marketing and business development agency specialized in luxury hospitality, real estate, and retail. Since 2016, we have helped clients around the world grow through strategic branding, 360 marketing, and high-impact campaigns...
Merlot Red Studio partners with ambitious brands to create elevated, high-impact design and digital solutions that define luxury, build trust, and drive desire. We specialize in crafting premium Brand Identities, Packaging, Website development, and Digital Strategies for brands that want to be remembered...
Humanizit is a full-service marketing agency based in Munich that helps small businesses and freelancers grow their visibility, connect authentically with their target audience, and increase sales through strategic branding, social media management, content creation, web design, and tailored marketing...
SEO Summer is a leading Melbourne-based digital agency specializing in SEO and web design. Founded by a team of passionate digital marketers in Melbourne, we are dedicated to helping businesses of all sizes achieve outstanding online visibility and growth...
We are a team of website designers, online marketers, graphic designers and programmers based in Reading with over 5 decades of experience combined in Website Design, SEO & Online Digital Marketing...
Execution. Performance. Results | Award-Winning Digital Marketing Agency
Execution. Performance. Results | Award-Winning Digital Marketing Agency
Multi-award-winning digital marketing agency. We create commercially-focused digital marketing campaigns designed to help you reach your KPIs and maximise ROI...
Vilni Group is a London-based design and growth studio helping tech, SaaS, and modern B2B companies build brands, products, and websites that drive real business results. We combine high-end UX/UI, Webflow development, brand identity, and performance marketing into one streamlined process. Fast...
Invanity is the revenue-first marketing agency. That means we refuse to separate marketing from commercial outcomes. Everything we do is built to create desire, capture demand, and bring the repeatable revenue that fuels growth...
[Welcome to the Nexus] A central point where strategy and execution meet to produce real results. A laboratory of creativity and intelligence. A launchpad for businesses ready to move past the noise and into the next phase of their evolution...
We Build Your Reputation on Reddit. We Secure Your Spot in AI Answers.
We Build Your Reputation on Reddit. We Secure Your Spot in AI Answers.
Red-engage is a Generative Engine Optimization (GEO) and Reddit marketing agency. We help B2B brands get cited in AI answers from ChatGPT, Perplexity, and Gemini while building authentic community trust on Reddit...
Biz Emporia is a results-driven digital marketing agency focused on helping businesses grow visibility, authority, and revenue online. We specialize in brand development, web design, SEO, performance marketing, and lead generation, delivering strategies that are data-backed, conversion-focused, and scalable...
Jasper helps brands grow with bold identities, strategic SEO, compelling content, and stunning web designpowered by agile collaboration and expert creativity...
Use "Video Content Systems" to transform your social media followers into warm leads and prospects. In 2025, personal branding is what sets the ultra-successful apart from those who fall flat. What would it mean for prospects to show up for your sales calls warm and ready to buy? That's the power of how we...
Advance Online provides a range of digital marketing services to build and improve your overall online presence. From web design to SEO, content marketing to PPC, we'll help your business get seen by the right people, at the right time, in the right place...
London Video Production Agency for Brands, Events & Social Media
London Video Production Agency for Brands, Events & Social Media
Shootlab is a video production and content creation agency specialising in event videography in London, corporate video production, and social media video editing services. We produce narrative-driven marketing films, promotional videos for websites, and short-form video content for Instagram Reels,...
We are not your typical Vancouver web design agency. We create websites that not only look great but also rank great as well. From websites and mobile apps to SEO, our team of experts can take your business to the next level. Our well-designed and optimized websites increase organic search engine traffic...
Our work is driven by inspired individuals. A growing network of peers who express their talents with clear sincerity and devotion. Backed by groundbreaking vision, technology and extensive personal experience we design brands that are vibrant, touching and alive...
Your agency for search engine marketing & social media advertising.
Your agency for search engine marketing & social media advertising.
We specialize in search marketing optimization (SEO), Google Ads (SEA) and social media advertising. As a highly visible Google Partner with individual strategies, you can have online visibility and follow-up. Our goal is to achieve measurable results with more efficient management, efficient management and...
THE POSSIBILITIES ARE ENDLESS. JOIN US TO EXPLORE THEM ALL.
THE POSSIBILITIES ARE ENDLESS. JOIN US TO EXPLORE THEM ALL.
At Marketing Planet, were on a mission to transform marketing through innovation. We use cutting-edge technology to deliver highly personalized, sustainable, and effective campaigns. With a focus on ethical data handling, real-time analytics, and seamless integration, we help our clients build lasting...
PR and personal brand support that actually gets noticed. From headline-grabbing media coverage to LinkedIn strategies that work, we help founders, leaders and brands show up with clarity, credibility and confidence. Big-brand thinking, boutique feel...
A results-driven, feed disrupting marketing agency. We create strategic campaigns, blending creativity, best practices and commercial goals to ensure every message resonates with your audience. Based out of Salisbury and working with brands across Wiltshire, Hampshire, Dorset and Surrey...
CNV Creative is an outsourced marketing department for founders who are done being their own CMO. We build ROI-driven marketing systems that replace chaos with clarity aligning strategy, execution, and reporting so growth is predictable, profitable, and sustainable. Our work blends psychology, data, and...
Libanza Films is a Bangladesh-based video production company specializing in strategic, cinematic, and results-driven visual content for brands, organizations, and institutions. We deliver end-to-end production solutions from concept, scripting, and storytelling to filming, post-production, and multi-platform...
Inspec Marketing is for Industrial and technical teams. We're a results-driven marketing agency, with boots-on-the-ground experience that sets us apart from generic agencies and makes us part of the industrial world. We work with future-focused Industrials – from startups to global heavyweights enabling...
Geeks360 is a US digital marketing agency built on one motto: Where AI Meets ROI. Since 2011, we've helped small and mid-market businesses stop wasting ad budgets and start seeing marketing as a profit center. Our team combines AI-powered analytics with hands-on expertise across SEO, AI-search visibility...
Custom Digital Solutions for Websites, Apps, SEO, and Marketing
Custom Digital Solutions for Websites, Apps, SEO, and Marketing
Aplus Tech Solutions helps businesses enhance their online presence by creating custom websites and apps, while also managing their digital marketing through SEO, social media management, and branding...
Were a B2B tech marketing agency on a mission to help IT, MSP, and telecom brands grow smarter and faster. From strategy to storytelling, we turn complex ideas into bold, engaging campaigns that get results across markets, across borders...
Services To Power Return On Your Marketing Investment
Services To Power Return On Your Marketing Investment
At MetacortX we create human-centered, insight-driven digital strategies that drive growth through UX, SEO, loyalty, and analytics. We can help your business optimise operations today and strategically plan and innovate for the future...
Firm Focus Marketing is a results-driven digital marketing agency dedicated to helping businesses grow through smart, data-backed strategies. We specialize in SEO, content marketing, and lead-generation blogs that boost visibility, build authority, and drive consistent growth. By combining innovation with...
Marketing and Lead Generation Tailored To Your Business Goals.
Marketing and Lead Generation Tailored To Your Business Goals.
Sembility is a 360 digital marketing agency. It specializes in SEO and lead generation via LinkedIn and other social media. At Sembility, our client's return on investment is key to us. Our goal is to effectively implement campaigns for you. Building our experience since 2015 in digital marketing, we have...
Surprisingly different rebellious southern creativity
Surprisingly different rebellious southern creativity
Blue Ridge is a southern creative marketing agency in the business of building bold brands, websites, and campaigns for hospitality, cannabis, and healthcare companies that are done blending in. The South has always had a distinct point of view... so do we...
Marketing & Advertising Solutions for Any Condition.
Marketing & Advertising Solutions for Any Condition.
At the core of our mission lies the commitment to tailor marketing solutions according to your unique requirements, avoiding generic and standardized approaches. We are staunch proponents of crafting influential strategies that resonate with your brand's essence and principles, fostering profound connections...
FamilyStuff.in is a creative SEO and web design agency helping businesses grow online with smart digital marketing, responsive websites, and data-driven SEO strategies tailored for lasting success...
Origin Story is an independent marketing consultancy. We champion small business owners by serving as the marketing partner who not only lightens their workload but also propels their business to new heights. We help you launch eye-catching marketing campaigns to elevate your brand and keep you top of mind...
Need a creative spark to light up your brand? Look no further, NU Creative is here! Our multi-award winning London based B2B agency has what it takes to bring any business back into the limelight. We'll never be afraid of shaking things up with our 'out-of-the box' thinking - helping you stand out from all...
We don't design for brands. We design for people interacting with brands.
We don't design for brands. We design for people interacting with brands.
We are a team of creative minds and brand strategists with expertise that extends across brand architecture, design, digital marketing communications, and user experience. Our primary goal is to assist brands in transforming into platforms for exceptional content and design, fostering a strong connection with...
7 Frequently Asked Questions About Content Marketing Agencies
What do content marketing companies do?
Content marketing companies create and distribute digital content intended to inform, attract, engage, retain, and inspire action across target audiences. The main goal of their produced work is to drive greater brand awareness, boost organic traffic and SEO rankings, and guide prospects through the buyer's journey to ultimately increase leads and sales.
What services do they provide?
Key services provided by content marketing agencies include:
Content strategy development: Curating bespoke plans to align content with business objectives, ideal customer profile (ICP) intent, and industry trends.
SEO copywriting and keyword research: Optimizing content to rank higher in search engine result pages (SERPs) and improve visibility to potential customers.
Editorial management and publishing: Sourcing writers, editing content, managing content calendars, and handling the publishing process.
Distribution and promotion: Making sure the content reaches the target audience through social media, email campaigns, and paid advertising.
Performance analysis: Monitoring how content performs and tracking traffic, engagement, and conversion rate metrics to refine strategies.
How much does a content marketing company cost to hire?
Across the US, a content marketing company usually charges between $100 to $500 per 1000-word post.For social media content, the price usually goes between $50 and $150 per post.
The final price can vary based on a combination of factors:
Length and topic complexity: Shorter, simpler posts cost less compared to in-depth, longer articles.
Expertise: Posts requiring niche knowledge or specific writing style entail higher fees.
SEO adjustments: Extending the service with SEO services like keyword research and integration can also raise the price.
Additional services: Content promotion, social media sharing, and visual add-ons count as an addition to the base fee.
How long do different content pieces take to write?
Short, standard articles can take an experienced writer 1 to 3 hours to write, while research-heavy pieces may require over 10 hours. Same as with pricing, the topic complexity and research requirements affect the writing time as well.
In general, seasoned writers can produce 500 words in 30 to 60 minutes, while for the same work, a beginner might need 2 to 3 hours or more.
Here are some average time estimates by content type:
Social media posts/short content (75 to 300 words): 30 minutes to an hour
Standard blog post/article (500 to 1000 words): 1 to 3 hours (assuming moderate research)
1,500-word piece: 3 to 6 hours, depending on depth
Long-form, 2,000-word content piece: 6 to 10+ hours
Technical content piece: Up to 10 hours per 500 words, given the need for extensive research and citations
Full website content coverage (20 pages): 11 to 40 days, depending on the complexity of the brand voice and required research
What types of businesses benefit most from working with a content marketing agency?
Small businesses, startups, expanding brands, and companies looking to set or correct a brand image benefit the most from a content marketing collaboration.
Businesses starting from the ground up benefit a lot from a content marketing agency as it maps out a clear strategy and builds an audience from day one. Companies dealing with a bad reputation or a complex rebranding phase also see considerable returns, as a good agency can use honest storytelling to fix misconceptions and win back trust.
At the same time, if a brand is entering a new market or launching a unique product line, specialized content helps them spread the message more easily by producing pieces in the local language.
How long does it take to see results from content marketing services?
Content marketing follows a more extended trajectory as it takes time for search engines to recognize and rank the content. As the content library expands and gains credibility, brands start to see incremental growth in 3 to 6 months.
The same goes for social media: as content compounds and reaches more people, the organic traffic gets steadier and lead generation efforts start gaining more traction.
How is content marketing different than SEO?
Content marketing is the substance, i.e., the strategy of creating value to build a relationship with the intended audience. SEO is the visibility or the technical process of making that value discoverable by search engines.
Essentially, they are two sides of the same coin: SEO makes demands (keywords, structure), and content marketing fulfills them.
Across both practices, quality comes first. Namely, if the piece is optimized for a search engine but fails against the intent of the reader, the content will eventually lose its rank because it lacks topical authority.