Guy Marks

Guy Marks is a senior global media executive who stepped into the role of Global Chief Client Success Officer at Omnicom Media in 2026, following a distinguished tenure as Global CEO of PHD, one of Omnicom's flagship media agency brands. In his current role, Marks is responsible for ensuring that Omnicom Media's clients receive integrated, high-quality service and outcomes across the group's full portfolio of agencies and capabilities, reflecting the industry's growing emphasis on client retention, satisfaction, and measurable business impact. As Global CEO of PHD, Marks led one of the world's most creatively recognized media agencies, overseeing its strategic direction, talent, and client relationships across a global network. PHD has long been distinguished by its thought leadership and planning philosophy, and Marks played a central role in evolving the agency's offer in an era of rapid digital transformation, data-driven media, and shifting client expectations. His leadership helped position PHD competitively against rival networks during a period of significant industry consolidation and technological change. Marks brings deep expertise in global media strategy, client leadership, and agency management, with a career spanning major holding company environments. His elevation to a group-level role at Omnicom Media signals the organization's commitment to placing client success at the heart of its operating model, a priority that has become increasingly critical as advertisers demand greater accountability, transparency, and business outcomes from their agency partners.

Last updated Jul 10, 2026 by ATDb automated enrichment · Connections updated Jul 13, 2026