He has handled some of the most iconic footballers - Eric Cantona, Roy Keane, Peter Schmeichel, David Beckham and Ryan Giggs - and established United among the most commercially successful sporting products in the world.
"There have been so many wonderful players at the club and it has been a pleasure and an honour working with them," he said.
"There's nothing I like better than to pull my car into the training ground of a morning and look forward to another few hours working with them and my staff.
"There's an awful lot of trepidation about the job. Being manager of Manchester United carries a tremendous responsibility but hopefully I have been, and will continue to be, able to handle it.
"Any manager would be thankful to remember one great squad; I've had five or six."