The 33-year-old — the record goalscorer for both his country and Manchester United — signed an initial 18 month contract with the ambitious second tier side, who under Rooney’s former England team-mate Frank Lampard reached the play-off final last season.
The high-profile signing has already paid off for the club.
“On the back of Wayne joining the club, we have just been offered a record-breaking sponsorship deal with our principal shirt sponsor,” said owner Mel Morris.
Derby, two-time English champions back in the 1970s, have been rewarded for being quick off the mark when rumours surfaced that Colleen, Rooney’s wife and mother of their three children, was unhappy in the United States and wanted to return home.
Rooney, who is presently working towards securing his coaching qualifications, will work under former PSV Eindhoven boss Phillip Cocu.
“I am very excited about the opportunity that Derby County have provided me with,” Rooney told the club website.
“I am looking forward to joining Phillip Cocu, his coaching staff and the first-team squad from the start of January.
“I am sure I can make a big contribution and can’t wait to meet everyone, especially the supporters.
“I am equally excited to begin my coaching career at Derby County working with both the first team and academy.
“I must also take this opportunity to thank DC United, their owners, executives and supporters who have been superb to work with.
“I want them to know that I will give my all in support of our push for the play-offs.”
– ‘Confidence or swag’ –
Steve Kaplan and Jason Levien, co-chairmen of DC United, praised Rooney for his contribution to the franchise — he has scored 23 times in 42 appearances since he joined from Everton on a three-year contract last year.
“After speaking to Wayne and understanding his difficult situation of being so far away from his family, we have accepted that this is the best decision for all parties,” they told the Derby website.
“Wayne is an exceptional leader and one of the most iconic players to play the game, so we look forward to his continued contributions to the team this season.”
Morris said Rooney’s arrival would bolster the reputation of the club.
“To have Wayne Rooney as a player, and equally as an aspiring coach, is incredible and I can only imagine the buzz this will generate amongst our supporters at home and internationally,” said Morris.
Cocu, who began his spell as manager with a 2-1 win over Huddersfield on Monday, said Rooney’s experience would be a massive boost to the club as they seek to return to the Premier League for the first time since 2008.
“It is an exciting prospect for him to be joining Derby County and he can bring so much to this squad, both on and off the pitch,” said Cocu.
“To have a player with his leadership, skill, experience, character and work ethic will be huge for us.
“The inspiration and motivation this can generate is massive for all of our players from the first team right through to the youngsters in the academy.”
Morris will be hoping Rooney wields a similar influence that he has done at DC United as attested to by his team-mate Steve Birnbaum.
“He’s changed everything, he’s changed the culture of the club,” Birnbaum told the Daily Telegraph.
“The work ethic he puts in during practice and you guys see it in the games. We have this sort of confidence or swag going into games because of him.”