The UK chairman since 2002, O'Donnell takes charge of OgilvyOne's European operations, which includes OgilvyInteractive, in 28 countries.
He will report to OgilvyOne worldwide chief executive Brian Fetherstonhaugh and Ogilvy EMEA chief executive Mike Walsh.
Walsh said: "Paul's expanded role in Europe will provide fresh leadership and thinking as OgilvyOne enters a period of greater market buoyancy."
O'Donnell began his 20-year Ogilvy career at the then O&M Direct in London and went on to become a regional leader of OgilvyOne in Asia and Latin America.
O'Donnell added: "This is an exciting time for our European business. Media models are evolving rapidly and major advertisers are increasingly open to the kind of channel-neutral thinking that OgilvyOne has pioneered."
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