Jenner succeeds former Wavemaker Global CEO Tim Castree, who became GroupM's North American chief executive officer last December. Jenner will take on a team of 8,600 employees who manage $13 billion in billings for blue-chip clients in 90 countries.
A GroupM spokesperson says Jenner's successor at MediaCom "will be announced soon."
Jenner will report to GroupM Global CEO Kelly Clark who called him an "outstanding contributor to our group's growth for more than 15 years." Before becoming the chief operating officer of MediaCom, Jenner served as the company's global chief business development and marketing officer, the chief operating officer for its Asia-Pacific region and CEO of its Australia region.
"In his 11 years at MediaCom, he's been instrumental in delivery of breakthrough client work, a winning streak on award circuits regionally and globally and powerful business development performance," Clark said.
Prior to MediaCom, Jenner was the managing director of WPP's MEC in the U.K. from 2004 to 2008. MEC launched Wavemaker as its specialty content division in 2016. In 2017, Wavemaker emerged as the name of the agency formed by the merger of MEC and Maxus, described as a hub for media, content and technology.
Since its 2017 launch, Clark said Wavemaker has also invested "heavily" in capabilities including precision marketing and commerce.
"I'm fortunate to join a business with very strong local markets, a great team, a great client portfolio and a track record in delivering growth for brands," Jenner said. "Like any business, I'm sure there are areas where we can be stronger. We'll address those as a team and take the agency on to even greater success moving forward."
Jenner will remain based in London but is a "well-practiced traveler as a global executive," the GroupM spokesperson said, so "he'll be in New York and other major markets and business centers within Wavemaker's global network often."