O'Brien, the former marketing director of Clear Channel UK, will join Universal on 14 November as it bids to build its resources in the research field.
Her arrival will free Glen Parker, Universal's research director for Europe, the Middle East and Africa, to focus on his international role.
Part of O'Brien's task will be to make some hirings to beef up Universal's headcount on the research side.
O'Brien is Universal's second senior hiring this year. It has also rehired Abba Newbery as its strategy director. Newbery replaced Martyn Stokes, who left the agency to join Media Planning Group as its strategy director.
Damian Blackden, the joint chief executive of Universal McCann, said: "Yvonne really stood out from the other candidates. She's got a useful background in both marketing and research, which will help us deliver more actionable, real-world insights and engagement."