The Portuguese has been linked with the Old Trafford hot seat ever since being sacked by Chelsea in December, following an abysmal run of results that left the then-reigning champions just two places above the relegation zone.
But reports of the 53-year-old taking over at Manchester United escalated drastically after Louis van Gaal was relieved of his managerial duties on Monday morning – just days after leading the Red Devils to the 2016 FA Cup.
The Special One and agent Jorge Mendes have been in talks with United since Tuesday and it the parties have reached an agreement, with Manchester United confirming him as their new manager on their official website.
The Portuguese has agreed a three-year contract with the option of a further year, which could see his stay at Old Trafford span beyond 2020.
Chief executive Ed Woodward said; “José is quite simply the best manager in the game today. He has won trophies and inspired players in countries across Europe and, of course, he knows the Premier League very well, having won three titles here.
“I’d like to take this opportunity to welcome him to Manchester United. His track record of success is ideal to take the club forward.
Mourinho, meanwhile, told reporters; “To become Manchester United manager is a special honour in the game. It is a club known and admired throughout the world. There is a mystique and a romance about it which no other club can match.
“I have always felt an affinity with Old Trafford; it has hosted some important memories for me in my career and I have always enjoyed a rapport with the United fans. I’m looking forward to being their manager and enjoying their magnificent support in the coming years.