Manchester United defeated Southampton 3-2 thanks to a brace from Zlatan Ibrahimovic to lift their 42nd major trophy, most by any English club.
After the match, Manchester United players celebrated their hearts out this being the first trophy of the ongoing season.
But Mourinho kept his celebrations low key and never went jubilant after the triumph.
When asked about his low-key profile after the win, he said: "It's for them, it's for the fans. I take this because I've won it four times. I take this for me.
"It's the first one plus the Charity Shield. For the development of the team, there's nothing better than doing it with the feeling of trophies.
"Now we have the Premier League, Rostov in the Europa League and Chelsea in the FA Cup and lots to prepare for.
"I could feel today the difference in freshness between one team and another one.
"I think if it went to extra time we'd be in trouble so I had to compact more the team and try and give some stability to the team because the fuel was in their legs - not our legs."
The Portuguese manager stressed on the fact that the season is only half done and they still have many important matches to play.
The Red Devils take on FC Rostov in the round of 16 of the Europa League and face Chelsea in the quarter-final of the FA Cup.
Also Manchester United are very much in the contention to finish among the top 4 in the English Premier League.