Tamara Ingram is leaving as chairman of Wunderman Thompson.
Ingram was formerly J Walter Thompson's global chief executive and was appointed chairman after the merger of JWT with Wunderman in 2018. She will leave the agency later this year.
Mel Edwards, Wunderman's global boss, was named Wunderman Thompson global chief executive after the merger.
Before she leaves, Ingram is moving to a new role as non-executive chair. Her leaving date has not yet been announced.
At JWT, Ingram replaced Gustavo Martinez, who departed the company after being sued for sexual harassment by former chief communications officer Erin Johnson.
Mark Read, WPP’s chief executive, announced Ingram’s departure in an internal memo.
He said: "When Tam was named worldwide CEO of J Walter Thompson in 2016, she made history as the first woman to lead the agency.
"Later, when I spoke to Tam and Mel about bringing JWT and Wunderman together during 2018, Tam embraced the idea and worked closely with Mel to integrate the two agencies – creating a single powerhouse built to inspire growth for its clients."
WPP has been asked to comment.