Beto O’Rourke has hired a former top aide to Barack Obama to be his campaign manager, installing a seasoned political strategist to take the helm of what has so far been a skeletal organization effectively overseen by Mr. O’Rourke himself.

Jennifer O’Malley Dillon, a data expert who was Mr. Obama’s deputy campaign manager in 2012, said in an interview Monday that she was going to work for the 46-year-old former Texas congressman because he represents “a new generation of leadership I think we need.”

Ms. O’Malley Dillon was one of the most sought-after Democratic operatives of this election, and her hiring suggests that Mr. O’Rourke is willing to professionalize his presidential bid in a way he resisted during his electrifying but unsuccessful Senate campaign last year.

A former executive director of the Democratic National Committee, Ms. O’Malley Dillon, 42, has worked on five presidential races and a number of other campaigns.