The Portuguese boss was appointed as van Gaal’s sucessor in May and won his first trophy as Man United manager in his first competitive game in charge.
“I want to dedicate this to eight people,” he said.
“He won the FA Cup. Without him, we wouldn’t be here now celebrating.”
News of van Gaal’s departure as Man United manager came only moments after his side won the FA Cup final against Crystal Palace in May.
Since then, Mourinho has completed the signings of Zlatan Ibrahimovic, Eric Bailly and Henrikh Mkhitaryan, with the club announcing on Sunday afternoon Paul Pogba would be completing a medical at Carrington to finalise his transfer from Juventus.
Hopes are Mourinho will continue his success in the Premier League and help get the club back to their former glory days after disappointing tenures under van Gaal and David Moyes.