As Client Success Senior Director, you will play a pivotal role in delivering client excellence and driving marketing effectiveness. You will lead client partnerships across key accounts, acting as a strategic advisor who champions analytics-driven marketing performance.

This role requires a strong blend of leadership, commercial acumen, and deep marketing measurement expertise. You will work closely with senior client stakeholders, helping them unlock growth through data-led decisions, advanced analytics, and actionable insights.

Key Responsibilities

Client Leadership & Strategic Impact

• Serve as the senior point of contact for client executives, shaping and delivering marketing effectiveness strategies that align with their business goals.
• Champion the use of advanced analytics (MMM, attribution, testing) to influence high-value marketing decisions and demonstrate ROI.
• Translate complex insights into clear, actionable narratives that drive client confidence and stakeholder buy-in.
• Expand client relationships by identifying new opportunities and embedding Gain Theory’s marketing effectiveness frameworks into their strategic planning.

Marketing Effectiveness Delivery

• Ensure flawless execution of analytics projects, with emphasis on actionable outcomes and marketing ROI.
• Apply rigorous QA standards and marketing-centric storytelling to all deliverables.
• Collaborate with product teams to maximize client engagement with Gain Theory Interactive and proprietary platforms.
• Embed operational excellence, ensuring client deliverables are on time, in scope, and aligned with business impact.

Commercial & Financial Growth

• Identify and lead incremental growth opportunities across existing client portfolios, focusing on measurable marketing value creation.
• Support profitability by optimizing project scope, resource allocation, and client engagement models.
• Lead and support new business development, including RFPs and strategic pitches.

Thought Leadership & Industry Foresight

• Stay ahead of evolving trends in marketing effectiveness, data privacy, media, and consumer behavior to inform client strategy.
• Advocate for best practices in unified measurement and analytics maturity.
• Contribute to award submissions, industry panels, and Gain Theory thought leadership initiatives.

Team Leadership & Culture

• Inspire, mentor, and grow a high-performing Client Success team.
• Foster a collaborative, learning-first environment that aligns with Gain Theory’s values.
• Support team engagement, well-being, and retention initiatives.

KPIs & Success Measures

• Client Satisfaction & Advocacy Scores
• Net Sales Growth & Profitability
• Measurable Marketing ROI & Value Delivered
• Number of Senior Stakeholders Engaged
• Awards and Industry Recognition
• Employee Satisfaction (Client Success Practice)
• Operational Excellence Adoption

Your Profile

• 8+ years in client leadership roles within marketing effectiveness, consulting, or analytics.
• Proven track record influencing C-suite stakeholders and driving measurable marketing results.
• Strong expertise in marketing analytics and effectiveness (MMM, attribution, testing).
• Exceptional storytelling and communication skills, particularly around data and insights.
• A commercial mindset with a passion for client growth and value creation.
• Inspirational team leader who thrives in a fast-paced, high-impact environment.

About Gain Theory

Gain Theory is a global leader in marketing effectiveness and foresight. We empower ambitious brands to accelerate growth by delivering clarity and confidence in marketing investment decisions. Our work combines high-quality data, proprietary technologies, and advanced analytics to help brands outperform their industries.

We specialize in:

• Marketing Effectiveness & Foresight: Including MMM, attribution, unified measurement, testing, and forecasting.
• Data Strategy & Activation: From harmonization to visualization and simulation.
• Consulting & Capability Building: Industry benchmarking, bespoke roadmaps, and strategic activation.

At Gain Theory, growth is central—to our clients and to our people. We live by four core values: Be Curious, Be Positive, Act with Consideration, and Make it Better. Learn more about our values: www.gaintheory.com/our-culture-people-and-value