Mourinho, a multiple trophy-winning manager, replaced Louis van Gaal as head coach of the Red Devils, having twice been in charge at EPL rivals Chelsea.
Yet Beckham feels Mourinho’s move to Manchester is just what the club needs.
"I fully expect it to work," Beckham told Sky Sports News HQ. "With Jose leaving Chelsea and now coming back into the Premier League with United, for me it is a great move.
"I had huge respect for Van Gaal, but it did not work out the way people expected it to. But I think at the end of the day, now it is a new start for United.
"We have had a couple over the last three or four years, which is not the Manchester United style, who are used to a manager like Sir Alex Ferguson being in there for so many years."
Beckham feels the experience and knowledge the ‘Special One’ brings will make United a feared club once more, following their disappointing run in recent years.
“With Jose in there, he knows what he wants and how to get it, he knows how to win titles,” he said.
"I think that is what Man United definitely need to get back to and they need to get back to being feared again. Because we were always a club - and are still a club - that when teams come to Old Trafford, they know they are going to be up against it and they know they are probably going to lose. So that is what we need to get back to."
Beckham says he’s confident that United can take league honours in Mourinho’s first season in charge.
"I am going to have to say United," Beckham said when asked who will win next season's title. "I will always be on that side of the fence."