Less than a year after a WPP merger of the J. Walter Thompson and Wunderman agency networks, Jeff Dack has been appointed Canadian CEO of the new agency group.

Former president and CEO of J. Walter Thompson Canada Susan Kim-Kirkland, who also served as global CMO and CEO of JWT’s Chicago office, and who took on leadership duties within Wunderman Thompson Canada following the merger, has confirmed she is leaving the agency to pursue other opportunities.

Michel Sergio, formerly president of Wunderman Canada, will be transitioning into a client-facing role at Volkswagen, added an agency spokesperson.

Arriving from media agency Carat Canada, where he served as CEO, Dack will lead the “strategic vision, growth, operations and client relations” for Wunderman Thompson in Canada, whose operations span offices in Toronto, Montreal and Vancouver. He steps into the role Sept. 3 and will be based out of Toronto.

Before joining Carat in 2016, Dack held leadership positions at Lowe Roche and client-side at Jamieson Laboratories. Throughout his career, he has made agency stops at TBWA/Chiat Day, Zig, Cossette, GWP Brand Engineering and Taxi.

Wunderman Thompson has recently made a number of other leadership changes within its global offices, including that of Daniel Bonner as global chief creative officer of brand experience, Melissa Dorko as chief growth officer of Wunderman Thompson North America, and Liz Valentine as CEO of Wunderman Thompson West, which includes the Swift agency and the agency’s offices in California, Seattle, and Denver, as well as its mobile business.

Whereas Kim-Kirkland previously led operations for JWT in Chicago, the market is now part of Wunderman Thompson Central, led by CEO Ian Sohn. The region includes offices in Austin, Texas;  Minneapolis, Minnesota; and Memphis, Tennessee.

Kim-Kirland wrote in an email to strategy that her previous global CMO role was eliminated following the merger.