Former United striker Solskjaer, the current manager of Norwegian side Molde, will take charge of the first team with immediate effect and will remain in place as caretaker manager while the club looks for a new full-time boss.
Tottenham manager Mauricio Pochettino and former Real Madrid boss Zinedine Zidane are among the bookmakers’ favourites to take the United job on a full-time basis at the end of the season.
Mourinho was axed on Tuesday after just two-and-half years in charge at Old Trafford, with United in sixth place in the Premier League and facing an uphill task to qualify for next year’s Champions League
Alex Ferguson’s former right-hand man Mike Phelan will join the 45-year-old Solskjaer as first-team coach, working alongside Michael Carrick and Kieran McKenna.
“Manchester United is in my heart and it’s brilliant to be coming back in this role,” said the Norwegian. “I’m really looking forward to working with the very talented squad we have, the staff and everyone at the club,”
Executive vice-chairman Ed Woodward described Solskjaer as a “club legend”.
“His history at Manchester United means he lives and breathes the culture here and everyone at the club is delighted to have him and Mike Phelan back,” he said. “We are confident they will unite the players and the fans as we head into the second half of the season.”
David Beckham and Gary Neville sent their former teammate messages of support on social media.
United are hoping that Solskjaer, who coached Paul Pogba and Jesse Lingard in the reserves, will inject renewed positivity into an ailing side, whose under-performing players and drab style played a big part in Mourinho’s exit.
The Portuguese manager, who won three Premier League titles in two spells at Chelsea, spoke for the first time on Wednesday, adamant that he had a future without United but refusing to go into details about his departure.
“It’s finished,” he told Sky Sports News. “Manchester United has a future without me and I have a future without Manchester United, so why should I now be sharing with you or even with the supporters, any of my feelings?
“It’s over. That’s me and that’s the way I’ve always been and I was always very critical of managers that leave clubs and then they come out and they speak about details of what happened and who is to blame for and this kind of situation — that’s not me.”
Solskjaer is seen as a safe pair of hands who understands the club, as United target a return to the pinnacle of English football — a position they have ceded to bitter rivals Manchester United since Ferguson’s retirement in 2013.
Jaap Stam, who played alongside Solskjaer at Old Trafford, told Sky Sports News: “He knows the culture of the club, the fans like him. Ole is the type of manager, as far as I know, who wants to play attacking football, who wants to go forward.”
The club are understood to be looking to hire a head of football, reporting to Woodward, to oversee football operations — a role it is believed Mourinho had a long-standing reluctance about.
Solskjaer joined United as a player from Molde in 1996 and was part of Ferguson’s team that won the treble of the Champions League, Premier League and FA Cup in 1998/99.
He scored 126 goals in 366 appearances for United between 1996 and 2007, winning six Premier League titles, and in 2008 he became the club’s reserve-team manager, before taking the managerial reins at Norwegian club Molde, where he won two league titles.
The Norwegian’s first game in charge of Manchester United will be Saturday’s trip to former club Cardiff.
Solskjaer managed the Bluebirds between January 2014 and September 2014, failing to stop them being relegated from the Premier League, returning to Molde in 2015.