In his second cycle, he was re-appointed to his former job in 2014/15 and he won the Premier league again as if he never went away.
"I'm so happy to be the manager of these guys, I told them a few days ago that during my long career I never had a group that I liked so much, like I like them", he said, after United's 2-1 loss to Real Madrid in the UEFA Super Cup in Skopje on Tuesday.
Victory in both the EFL Cup and Europa League were a sign that the Red Devils have taken a positive step back to becoming one of the top teams in European football. The Champions League is obviously more hard.
He has been at City since age 6, and was selected on the bench for the Champions League game against Celtic in December. I understand by doing 75 percent of what I asked, the club did very well. I'll just go with everything I have to try to win every match we play.
"You know, he's injured, he needs time to recover", the United boss said.
"I was surprised to see him move to United and maybe there is more to this deal that we realise", stated the former England midfielder, who is moving into television punditry with BT Sport this season.
Yet, a team featuring Sergio Aguero and Gabriel Jesus up front and a sprinkle of attacking midfielders like Kevin De Bruyne, David Silva, new signing Bernardo Silva, Leroy Sane and Raheem Sterling promises lots of goals this season.
"Everyone knows that I stopped my global career, so I had a good break".
Ahead of the Premier League opener against West Ham at Old Trafford on Sunday, he said: "My initial analysis from January and progressing through other months I was thinking of four players but I am not a hard person to work with, even if looks different or you want to make it look so".
While Mourinho has welcomed the new signings, he argues that of greater significance is the fact his team will not have their domestic fixture list disrupted by the Europa League this season.
The 29-year-old Mexican, known as "Chicharito" (Little Pea), was a crowd favourite during his five years at United, scoring 59 goals for the club and playing a part in two league title successes.
City have spent nearly £150m on the current transfer window and only one of his five signings to date has not been to strengthen his back-line.
"Overall I believe that it's down to us".
Mourinho's mission is clear - to add to his three trophies captured in an impressive debut season at Old Trafford.
"This time, we are all in the same basket".