Client Strategy & Operations Lead (Founding Role) in London

Location: London, Victoria

Type: Full-time, in office

About thirdflow

thirdflow is a fast-growing B2B media agency focused on one thing: helping B2B companies create predictable, compounding demand. We design and run content-led demand generation systems that are built to drive pipeline and revenue, not vanity metrics. Our work sits at the intersection of strategy, content, and distribution, with a strong focus on what actually converts.

thirdflow was founded by operators who have built and scaled multiple B2B media and services businesses. We work with ambitious teams who want marketing to be a core part of how they grow. Alongside our agency work, we also build and operate our own B2B media brands, including content platforms and live events focused on fast-growing niches. These media properties give us first-hand insight into what actually drives attention, trust, and demand, and they inform how we work with clients day to day. Over the next few months, we plan to launch additional media brands and events, expanding our footprint across multiple B2B sectors.

Our Culture

We are builders and entrepreneurs. That means moving fast, experimenting, and continuously improving. We value clear thinking, strong execution, and the ability to turn ideas into measurable results. We’re in a strong growth phase, which means we’re still shaping and refining our playbook. You’ll be joining a lean, driven team where ownership and accountability matter more than job titles. This is not a role for someone looking for a clearly boxed job or a slow ramp-up. It suits someone who enjoys being close to the work, close to clients, and close to the decisions that shape the business.

The Role

We are hiring a Client Strategy & Operations Lead to take ownership of marketing delivery and client operations at thirdflow. This is a senior, hands-on role for someone with real B2B marketing experience who is comfortable leading strategy while staying close to execution. You will work closely with the founders and will be trusted with real responsibility from the outset. The role is hands-on and client-facing, with a strong focus on making sure our work delivers measurable results and can scale as the business grows. This is a founding role. As thirdflow scales, there is a clear opportunity for this position to grow into a C-suite role, including responsibility for building and managing a team.

What You Will Do

• Own day-to-day client relationships and be accountable for marketing delivery, performance, and outcomes
• Lead the strategy and execution of content-led demand generation programmes across channels including paid, organic, email, partnerships, and owned media
• Oversee content production across formats such as articles, reports, podcasts, video, and social
• Track performance and report on results, identifying what is working, what is not, and what we should change
• Build and document repeatable delivery processes to improve consistency and scalability
• Work with clients and partners to develop credible thought leadership and campaigns
• Support the founders on high-priority operational and strategic projects as the business grows

What Success Looks Like in the First 6 Months

• You fully own client delivery and relationships with minimal founder involvement
• Our demand generation and content processes are clearly documented and improving month on month
• Clients trust you as their main point of contact and strategic lead
• Delivery feels more consistent, predictable, and scalable
• You have identified gaps in our capability and what we need to hire or build next

Who This Role Is For

This role is suited to someone who:

• Has 2+ years’ experience working in a high growth marketing agency startup, VC or consultancy environment
• Has extensive knowledge and passion for B2B marketing and how to close high ACV clients
• Has owned or led content, demand generation, or GTM programmes
• Has been client-facing and accountable for delivery and results
• Is comfortable operating in a fast-moving, early-stage business
• Enjoys balancing strategic thinking with hands-on execution
• Takes ownership seriously and does not need heavy oversight
• Wants to grow into a senior leadership position as the business scales

Why Join thirdflow

• A founding role with real influence over how the agency operates and grows
• Direct exposure to company building and decision making
• Responsibility and trust from day one
• An opportunity to work with some of the fastest growing media companies in Europe and enterprise clients
• Clear progression into senior leadership as the business scales
• Competitive salary, performance-based bonuses, and long-term upside for the right person
• Personal development budget and learning opportunities

How to Apply

We are more interested in how you think and operate than in polished cover letters. Please submit your application, including a detailed resume, references, portfolio, and a cover letter explaining why you’re the ideal candidate to drive our company success forward. Applications should be sent to careers@thirdflow.co.uk or directly on Linkedin. thirdflow is an equal opportunity employer. We value diverse perspectives and are committed to building an inclusive, high-performing team.