The 25-year-old grew into the tournament and the spectacle of him shining on the biggest stage came in stark contrast to a fractious season under Mourinho at Old Trafford.
Pogba found himself left on the bench for both legs of the Champions League last-16 defeat to Sevilla and was withdrawn during losses to Tottenham and Newcastle United, as speculation mounted over a breakdown in relations with his manager.
Speaking at his first news conference of United's pre-season tour of the United States, Mourinho confirmed he passed on congratulations to Pogba and hailed his performances during the latter stages of the competition.
The United boss now hopes the club's record signing has the awareness to bring this form into the Premier League.
"I hope that he understands why he was very good," Mourinho said.
"I think that's the point about his performance level and his contribution to a winning team – for him to understand why he was so good, especially in the second part of the competition.
"In the quarter-finals, semi-finals and final he was absolutely brilliant."
Mourinho added: "To win the World Cup can only be a positive thing. It’s difficult to say that to win the World Cup is not good for a player's career. So many good players never have the change to be a world champion.
"It's a young [France] team, apart from [Olivier] Giroud, [Hugo] Lloris and a few others they are all young and have more years to play together.
"The future for [Pogba] in the French national team, among that fantastic group of players, can only be brilliant."
Pogba's prospective new midfield partner Fred will join up with United's squad in the USA next week, while fellow new recruit Diogo Dalot is out until September with a knee problem.
Mourinho claimed he was unsure whether there would be further incomings to Old Trafford before the 2018-19 season gets underway in less than four weeks' time.
"I have no idea, I'm not going to lie to you," he said. "I'm not going to say something is coming. I'm not going to say nobody is coming. I really don't know."