The changes will see Bill Gray, currently co-CEO, become vice chairman, North America, focusing on a core portfolio of strategic accounts, and network developments.
John Seifert, who currently leads Ogilvy's global client organisation, which serves 25 global clients from the Ogilvy network, will assume the new role of chairman, North America.
Seifert is a long standing executive who has served in a variety of general management and client service roles in the US, Asia, and internationally.
Carla Hendra will continue in her role as CEO, Ogilvy North America and chairman of the New York Office -- and will report to Seifert.
Young said: "North America is our most important region. These changes provide the clarity of leadership which the new Ogilvy I envisage requires, and will allow three exceptional individuals to deploy their talents to their fullest potential.
"In John we have a leader who listens -- to our clients, our people, and the world around us. He is exceptionally well qualified for this role."