The 53-year-old is reportedly yet to sign a contract, but official confirmation from United is expected by Friday after the deal was delayed due to discussions over Mourinho’s image rights.
Mourinho is said to have been offered a three-year contract that will pay him £10 million ($14 million, 13 million euros) per season, which is double the salary earned by Van Gaal during his troubled two-year reign.
It was also reported Mourinho, who was sacked by Chelsea in December, is set to be given bonuses that will pay £5 million and £2.5 million respectively if he leads United to the Champions League or Premier League title.
It emerged Chelsea had owned Mourinho’s name as a trademark since 2005 and could demand a six-figure sum from United before his new club can use it to sell merchandise such as toiletries, technology, clothing and jewellery.
There was also a potential conflict between Mourinho’s personal deals and United’s own sponsors because the Portuguese coach has contracts with Jaguar and Hublot Watches, while United’s shirts sponsors are Chevrolet and they also have an arrangement with watchmaker Bulova.
But talks between Mourinho’s agent Jorge Mendes and United’s executive vice-chairman Ed Woodward are believed to have resolved those problems and look to have paved the way for the controversial and charismatic boss to fulfil his long-held dream of managing the Manchester giants.
Mourinho was seen strolling back to his town house in the upmarket London district of Belgravia wearing a smart black suit and clutching documents on Thursday, and soon after those images emerged it was reported he had agreed the deal.
Assuming there is no last-minute hitch, the former Real Madrid, Inter Milan and Porto boss will take charge of United for the first time when the club face Borussia Dortmund in Shanghai on July 22 on the first leg of two-game tour of China.
However, Mourinho should appear on the home bench at Old Trafford before then because he is due to take charge of an England XI in a charity game for Unicef against a Rest of the World XI on June 5.
Although United legend Eric Cantona this week claimed the acerbic Mourinho, renowned for his negative tactics, was not a good fit, the club’s former defender Rio Ferdinand was quick to welcome his impending arrival.
“I have heard many say the ‘Mourinho way’ is not the Manchester United style of playing football,” Ferdinand said.
“However, the Chelsea team that Jose put together first time round when he entered the Premier League played with wingers and hurt teams with quick attacking play.
“This is a sign he knows how to get a team playing in a way Manchester United fans can look forward to seeing.
“One thing I can tell Manchester United fans is that they have got themselves a true winner in all aspects. His CV shows success.”
After opting against hiring Mourinho when Alex Ferguson retired in 2013, the dismal failures of David Moyes and then Van Gaal have persuaded United owners, the Glazer family, to sanction the hiring of the controversial boss.
Mourinho’s second spell at Chelsea came to an embarrassing end, with the Premier League champions languishing near the relegation zone amid what the club called “palpable discord” between the manager and his players.
Yet his record as a serial winner, with 21 trophies including three Premier League titles and two Champions League crowns, persuaded United he was the man to rebuild a squad that grew increasingly disenchanted with life under the schoolmasterly Van Gaal.
The Dutchman led 10-man United to a 2-1 win over Crystal Palace in Saturday’s FA Cup final and hoped that would be enough to save his job.
But winning United’s first major trophy since 2013 wasn’t enough to make up for the team’s failure to qualify for the Champions League after they finished fifth in the Premier League.
With official confirmation of his appointment still to come, Mourinho is reported to already be lining up new signings.
Zlatan Ibrahimovic, who played under Mourinho at Inter Milan, is one target and on Thursday he hinted a move to Old Trafford could be on the cards.
The Sweden striker has left Paris Saint Germain and, asked if there had been an offer from United, Ibrahimovic said with a smile: “If you want action you bring Mourinho.
“I don’t give guarantees but there are concrete offers from the Premier League, so let’s see what happens.”