Cooper, the iAd head of creative and strategy, EMEA, at Apple, will report to Gerry Human, who has been promoted to chief creative officer at O&M.
Cooper will initially focus on the global Philips account before extending his remit to other clients.
Cooper has spent just over a year at Apple, having previously worked at Wieden & Kennedy as the global executive creative director. At W&K, Cooper was responsible for leading the creative and strategic output on the Nokia account.
He also spent two years as a creative director of Dare, where he oversaw the creative output of the agency’s London and New York offices.
Cooper has won 16 Cannes Lions and five One Show Interactive Pencils for campaigns spanning clients including Sony Ericsson, Lynx and Vodafone.
Human said: "Over the years, Brian has consistently produced outstanding creative work and he has the right kind of experience to handle complex global brands."
Cooper added: "Ogilvy’s Dove Facebook campaign really demonstrated to me that this is an agency looking to produce exciting, fresh work, relevant for the modern world."
O&M continues its search for a London chief executive to replace Hugh Baillie, who left the agency last year. Andy Bird, the creative director, also departed O&M last year.