In his second stint at Omnicom Group's Tribal, Mr. Parker rejoined in 2009 to serve alongside New York-based Richard Guest as co-president of U.S. operations. Mr. Parker spent a total of 12 years at the agency, which he helped launch in Canada.
"We value Mike personally and professionally and are grateful for his contributions to the agency over the past decade. We wish him great success in the next chapter of his life," Tribal's Global CEO, Paul Gunning, said in a statement.
Last year was a rough one for Tribal in the U.S. Revenue plummeted almost 40%, to $55.1 million, according to the Ad Age DataCenter. Tribal is recruiting for Mike Parker's replacement, according to a spokeswoman.
In recent months, Interpublic Group of Cos.' McCann has stabilized somewhat after hitting a few rough spots. It retained its Chevrolet business under an unusual partnership with rival holding company Omnicom Group. McCann has been attempting a turnaround under Nick Brien, who was named CEO in 2010.
Mr. Brien has introduced a new management team, with mixed success. Though some work is improving, McCann has yet to gain any significant clients amid the changes being made. Several longtime execs have left the agency, including Matt Freeman, who was global chief innovation officer at McCann Erickson (and, previously, CEO at Tribal).
In a sure sign that McCann's leadership overhaul isn't over, McCann Worldgroup has brought on Alex Spinelli, former chief technology officer at Thompson Reuters, as global CTO; and former TBWA spokesman Jeremy Miller as global chief communications officer for McCann Erickson Worldwide.