Kelly Clark, who was named global chief executive of Group M in 2016, will continue to lead the company.
"Irwin is a one-of-a-kind visionary, and his mark on our company and the entire media business is indelible. I am one of many in this industry who count Irwin as a friend and mentor. We’re glad that he will still be available to us and our clients in his new role," Clark said.
Gotlieb is credited with establishing the first spinout of a standalone media agency, MediaVest, in 1993. He joined WPP in 1999 to serve as the first global chief executive for Mindshare and subsequently launched Group M globally.
"I’m fortunate for the many opportunities this industry has afforded me, and I enter this new chapter with tremendous gratitude and optimism," Gotlieb said. "I thank Sir Martin [Sorrell] for his support over the years, and I’m excited about the opportunity to contribute to WPP’s continued market leadership in an advisory role."
Gotlieb was also the first media agency executive inducted into both the American Advertising Federation Hall of Fame in (2017) and the Broadcasting & Cable Hall of Fame (2007).
"Irwin has always been the driving force behind the creation and development of first, Mindshare, then Group M, and, more recently, WPP’s focus on developing our technology assets, first-party data and content," Sir Martin Sorrell, chief executive of, WPP, said "We will not miss him, however, as he will continue to be available to the group as a trusted strategic advisor."