Since his arrival there has been a notable upsurge of optimism around Old Trafford. An optimism that can be seen on both the players' and the fans' faces. There is an air of expectancy that to be honest hasn't been felt since the heady days of Fergie.
He arrived at Piccadilly train station under no illusions of how big a task he had embarked on. A task not made easier by the state of the club that the two previous managers had left behind.
Louis van Gaal had departed on the back of an FA Cup final victory that will guarantee his place in United folklore, but apart from that the reality is that the Dutchman's so called philosophy had left many scratching their heads in both disbelief and confusion including the players.
United desperately needed a leader who had the confidence to pick up a wounded club and inject a self-belief drastically lacking from the squad. Enter the self-proclaimed 'special one'.
The club backed his vision with the necessary funds to acquire Ivorian defender Eric Bailly, Armenian midfielder Henrikh Mkhitaryan along with the free transfer of the enigmatic Zlatan Ibrahimovic from PSG and to top it off the return of world record signing Paul Pogba.
Of course, this would mean that the squad would need trimming. Bearing that in mind Mourinho allowed a lot of fringe players to depart Old Trafford either on loan or on permanent deals. These included loan deals for the likes of Adnan Januzaj, Andreas Pereira and James Wilson and permanent moves for reserve team talents Will Keane and James Weir, who both joined former United assistant Mike Phelan at Hull City.
After a mixed pre-season which included a long trip to China to end up playing only one match, the Mourinho factor began to take take shape when United returned to England and lifted the Community Shield by defeating Premier League champions Leicester City at Wembley.
In the opening exchanges two new signings stood out. The first was Zlatan Ibrahimovic, who has netted four goals in four matches and at the back Eric Bailly, whose outstanding performances were rewarded with three man of the match awards. His impact and partnership with Daley Blind has kept Chris Smalling on the bench.
The early indications are that Mourinho likes the pairing of Pogba and Fellaini in the middle. Many thought Fellaini could be moved on but once again he has proved his critics wrong.
Henrikh Mkhitaryan has been used sparingly but his talent is clear for all to see and much more exciting times lay ahead for the first Armenian to grace the English game.
The return of Luke Shaw in the defence has been like a breath of fresh air and his justified return to the England squad is no more than he deserves after the horrific injury he suffered last year.
Question marks still hang over some of the United players as Mourinho tries to put all the pieces of his puzzle together. One thing is for sure, it doesn't matter how big a star you are if you are not in the manager's plans then you will be left out in the cold.
Juan Mata was sold by Mourinho to United during his second spell at Chelsea and this sparked debates about the future of the Spaniard. However, much to his credit Mata has proved that he still has much to offer the team.
It is a big task to win the league this season as normal service has been resumed with the big three United, Man City and Chelsea all making an early statement under new management. Having said that if any manager can achieve it then you wouldn't bet against Mourinho. The Portuguese maestro does have previous when it comes to pulling off the remarkable.
Next up for United is the derby which will see Jose reunite his rivalry with Pep Guardiola in a match that doesn't need any more intensity than usual, but will certainly get it in the build up to the Old Trafford clash.
All in all it's been a brilliant start to the season for the team and Mourinho can take pride in the fact that he is the first United manager to win his first four competitive games as club manager.
How the season will pan out only time will tell. The signs are there that the new man in the hot seat has the bit between his teeth and the fans have been given fresh hope after three years of mediocrity.
Thanks for reading.