Brien is expected to succeed John Dooner as CEO at the Interpublic Group agency network, according to reports.
Brien is currently worldwide CEO of Mediabrands and oversees the media agency networks Initiative, Universal McCann and Magna Global.
Mr. Dooner, now 61, was named CEO of Interpublic in December 2000. But after three years marked by a financial restatement debacle and criticism from the analyst community that he was too inexperienced for the role, he stepped back down and headed back to the agency network from which he came.
Other potential candidates for the CEO role have included McCann Worldgroup COO Eric Keshin and McCann Europe, Middle East and African CEO Brent Gosper.
McCann Erickson was appointed to handle the marketing of the London 2012 Olympics on a “payment in kind” basis.