It is Rooney's first job in management, and comes after he led Derby as player-manager after Cocu departed in November.
The 35-year-old will be aided by Liam Rosenior, Shay Given and Justin Walker as coaches. The trio retain their positions on Rooney's staff going forward, with Given moving to the position of first-team coach.
Amid that run was a string of four clean sheets on the bounce, the first time Derby had achieved such a run since they were under the stewardship of Gary Rowett in 2018.
He also had a stint in Major League Soccer with DC United before returning to English football with Derby County where he took up a player cum coaching role.
Wayne Rooney tried to make the announcement that he was ending his playing career low-key by announcing it at the same time as he was confirmed as Derby County manager on a full-time basis, but tributes to the former England and Manchester United captain still poured in on social media. The Stadium, Training Ground, the quality of the playing staff and the young players coming through and of course the fan base that has remained loyal and supportive.
'Despite other offers I knew instinctively Derby County was the place for me. Wayne Rooney's illustrious playing career is over.
Rooney retires as one of Man Utd’s greatest ever players
208 - Goals scored in the Premier League.
After an impressive showing for England at Euro 2004 he was signed by Alex Ferguson for United in a £27 million ($37 million) transfer.
He spent 13 years in Manchester United where he won the Premier League five times, the Champions League, the FA Cup, and three league cups.
The 35-year-old retires as the all-time top scorer for Manchester United and England.
What is the situation with Derby's takeover?
Di club dey expect new owners to takeover di club dis week, as current owner Mel Morris and Deventio Holdings Group bin don agree for di sale for November.
Intel replaces its CEO with VMware's Pat Gelsinger
Before that, however, Gelsinger was Intel through and through, having spent 30 years at the company from 1979 to 2009. Bob Swan speaks during an Intel press event for CES 2020 in Las Vegas in January 2020.