Jose Mourinho started his Manchester United career winning the Community Shield before dedicating the victory over Leicester to former boss Louis van Gaal.
A late winner from summer recruit Zlatan Ibrahimovic saw United record a 2-1 win over the Premier League champions.
Jesse Lingard, whose stunning extra-time volley won the FA Cup for the Red Devils in May, opened the scoring with a solo effort only for Jamie Vardy to equalise following a costly error from Marouane Fellaini.
But it was left to debutant Ibrahimovic to steal the show with an 83rd-minute header and deliver United their first trophy under Mourinho.
The Portuguese, who lost the Community Shield to Arsenal last season while still manager of Chelsea, then made the surprise move to toast his predecessor – thanking van Gaal for delivering the FA Cup before his sacking just two days later.
“I want to dedicate the victory to Louis van Gaal because without him we would not be here celebrating,” said Mourinho.
“He won the FA Cup to allow me to be back and have one more trophy.
“No one remembered they were there because of me but I remember I win this trophy because someone won before me and allowed me to be here.
“I left many trophies for other managers to win after me when I left the club and no one remembered they were there because of me.
“I dedicate it to him and to my seven players who were not involved. I have to make choices and sometimes they are choices which hurt me to look behind me and see players like (Memphis) Depay, (Phil) Jones, (Ashley) Young there.”
Mourinho also exchanged words with Juan Mata after the midfielder was substituted in stoppage-time, having only come on in the 63rd minute for Jesse Lingard. But he insisted the Spain international now understands why he was replaced.
He said: “They had a right-back who I thought was Rory Delap but it was not, it was (Luis) Hernandez throwing balls 50 metres into the box. The last minutes were difficult and I know I did something which was not nice to do and take Mata off but now he is fine because he understands what I did. I could not take (Marouane) Fellaini or Ibra off, they were important for the Rory Delap throw-ins and we wanted to win the game.”
Ibrahimovic won it after Vardy – following Fellaini’s poor back-pass – cancelled out Lingard’s first-half opener. The forward had a quiet debut after signing on a free transfer from PSG this summer but has targeted more trophies after a winning start.
He told BT Sport: “It feels good. The first official game, we play for a trophy and we win. This is my 31st trophy. I’m super happy. Hopefully I can win much more than this.
“Something big is going on with our team. We begin with a trophy. I feel very good. The team is fantastic. It is probably the biggest club I played in. The only one I can compare it to is Milan.”
Leicester matched United for long spells and Shinji Okazaki hit the bar in the first half before late pressure failed to find a leveller.
They begin the defence of their title at Hull on Saturday and boss Claudio Ranieri was pleased with their display.
He said: “I am very pleased with our performance, we are in pre-season and we played against a big team but we deserve, minimum, to play the penalty shoot-out. That’s football. When you have Zlatan Ibrahimovic you know he maybe doesn’t touch so many balls but he gets one right and he scores.
“I enjoyed and watched the same team as last season, only the result is against us. Before the match I asked for 120 per cent and they gave me 120 per cent.”