Senior Client Success Director in London

The Opportunity

We are seeking a Senior Client Success Director with deep expertise in Marketing effectiveness and econometrics to lead our most strategic client relationships and shape the future of our client success function. In this senior leadership role, you will serve as a trusted advisor to C‑suite executives, ensuring our advanced analytics solutions deliver measurable business outcomes while driving account growth and retention.

Project Delivery

• Ensures projects within remit are managed to time and scope. Highlights any risks to client lead.
• Puts in place robust quality assurance techniques and follows them to ensure work going to clients is right first time.
• Uses data and analytics interpretation skills to bring insights to life for a mid‑senior audience (i.e. most senior day‑to‑day client stakeholder).
• Is a strong data storyteller who can explain complex insights at a simple, impactful level to a variety of audiences.
• Ensures clients have full knowledge and training of Gain Theory Interactive, highlighting any bugs or enhancements to the GTI team.
• Ensures projects are following Operational Excellence process and that there is full adherence from Client Success team.

Financial

• Looks for opportunities to drive profitable growth for clients and take on incremental (e.g. 1‑30% growth) opportunities. Bring in client lead and senior team for larger opportunities.
• Identifies values driven for clients and looks to assist clients in recognising that value.
• Understands how decisions made on projects will impact profitability and looks to run more efficient processes or tighter management of scope, designed in consultancy with client lead.
• Understands how actions they take will impact overall Gain Theory profitability and looks to make the right decisions towards this at all times.
• Is involved in new business pitches as part of a wider team. May be expected to lead opportunities that do not need a large team.

Client Management

• Manages against SOW to ensure limited scope creep and slippages.
• Implements plans to drive higher client satisfaction across every metric, highlighting any issues to client leadership.
• Helps to increase the number of stakeholders and advocacy at the right level (e.g. most senior day to day stakeholder). Works with client leadership to embed plan.
• Works with client leadership on risk mitigation process, highlighting any risks early and working on plans to mitigate.

Thought Leadership

• Has sufficient knowledge of most of Gain Theory solutions, systems and ways of working to have a healthy conversation with a client in any aspect of Gain Theory’s offering. Is actively looking to learn in this space.
• Maintains a solid understanding of their clients’ industries, keeping up to date with key trends and seeking opportunities for growth.
• Maintains a good understanding of the marketing effectiveness industry, assessing for threats, challenges and opportunities that said industry presents to client relationships.

Values & Team

• Is an inspirational leader for Client Success Managers.
• Implements initiatives to improve Client Success team satisfaction within squad. Understands what drives employee satisfaction and looks to make things better for all.
• Facilitates collaborative learning and knowledge sharing to boost team capabilities.

KPIs & Success Factors

• Net Sales Growth
• # of Client Stakeholders
• Client Influence
• Client Advocacy
• Client Satisfaction
• Client Success Practice Area ESAT

What We Want From You

• 8+ years of experience in client success, consulting, or marketing analytics roles, with significant client‑facing responsibility.
• Demonstrated expertise in Marketing Mix Modeling and econometrics (model interpretation, ROI analysis, elasticity, attribution methods).
• Proven ability to lead, manage, and develop high‑performing Client Success teams.
• Demonstrated success in managing enterprise portfolios and influencing C‑suite stakeholders across global brands.
• Demonstrated ability to manage client relationships and communicate complex analytics to non‑technical audiences.
• Strong strategic thinking and problem‑solving skills.
• Strong commercial mindset with experience identifying new opportunities.
• Excellent communication, presentation, and stakeholder management skills.
• Proven project management experience, with the ability to manage multiple projects simultaneously.
• Skilled in tools such as Excel, PowerPoint, and at least one analytics environment (R, Python, or similar).
• Bachelor’s or Master’s degree in a quantitative field (e.g., Statistics, Economics, Mathematics).

Why Work for Us?

Gain Theory is committed to actively building a diverse, equitable and inclusive workplace where everyone feels welcomed, valued and heard, and is treated with dignity and respect.

What We Pride Ourselves On

• Growth and development
• Meaningful work
• Flexible by design
• Brilliant benefits
• Culture with Heart

What We Do

Gain Theory is a global marketing effectiveness and foresight consultancy. Our vision is to accelerate growth for ambitious brands by giving clients the confidence to make better data‑informed investment decisions. High‑touch consultancy powered by unique partnerships and proprietary technology is used to power our award‑winning solutions.

Who We Are

We are a people‑centric organisation whose culture is underpinned by 4 important values: Be Curious, Be Positive, Make it Better and Act with Consideration. We channel these values through our behaviours, in the way we work, and in the interactions we have with each other and our clients.

WPP (Gain Theory) is an equal opportunity employer and considers applicants for all positions without discrimination or regard to characteristics. We are committed to fostering a culture of respect in which everyone feels they belong and has the same opportunities to progress in their careers.

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