The Manchester United and England’s record goalscorer, has agreed an 18-month contract as player-coach at Pride Park, but will join in January.
Rooney flew into the UK on Tuesday morning to finalise a deal to return, cutting short his MLS sojourn with DC United.
The 33-year-old will wear the No.32 shirt when he arrives.
Speaking at his press conference unveiling on Tuesday afternoon, Rooney said: “My agent spoke to the club and the owners here.
“I had a decision to make and the decision to come and play here in England and develop as a coach with Phillip Cocu was too good to turn down.
“I’m looking forward to coming here in January and helping them towards promotion.
“Firstly, I’m a player and feel I have a lot of quality to bring to the squad. Secondly I want to learn from Phillip and his staff to gain experience for when I take the next step.”
