The Portuguese coach has been hotly tipped as the man to succeed Louis van Gaal at Old Trafford after the Dutchman was sacked by the Red Devils on Monday.
Mourinho has been in talks with United for the last two days but the deal was finally confirmed on Thursday afternoon, according to Sky Sports.
Former United defender Ferdinand, who is now a pundit for BT Sport, gave a thorough assessment of Mourinho’s arrival at Old Trafford on Thursday as he revealed his excitement at the move.
Ferdinand wrote on his Facebook page: “Congratulations to Jose on being announced manager of the biggest club in the world!
“This is Jose Mourinho’s most exciting and most challenging job yet.
“The first thing he needs to do is install ‘winning mentality’ back into the club. Get this ingredient back into the players but also the people that work inside the club day to day.
“Give them back that belief so it is breathing throughout the club again, which is so important. But doing the above in the Manchester United way is equally as important.
“I have heard many say the ‘Mourinho WAY’ is not the Manchester United style of playing football. 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. They had the likes of Robben and Duff on the wings who were direct and quick.
“This is a sign he knows how to get a team playing in a way Manchester United fans can look forward to seeing.
“Another doubt I keep hearing and being asked is, will he keep in with the tradition of the club which is bringing through the young players? For the moment, I can’t answer this, only time will tell.
“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 his recent unsuccessful time at Chelsea in the final year, I can assure you this winner is now a wounded animal which makes him such a mouthwatering appointment. Jose went from winning the League cup & Premier League to losing a dressing room at Chelsea and I am certain he will want to restore all of that very quickly.
“He will be desperate to silence the media who have been writing and saying negative things about him (he will have stored it all being the competitor he is) and will be as focused as ever.
“Mourinho’s huge personality is made for this great club, it’s what he has been waiting for. Wishing him all the best!
United opted to sack Van Gaal after two years in charge after the Red Devils ended up fifth in the Premier League table and missed out on Champions League qualification.
The Dutchman’s sacking came just two days after he led Manchester United to FA Cup glory.
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news