The Belgian says the Netherlands boss is a "great manager" and is optimistic that there is a "great future ahead" at Old Trafford, and also praised Ryan Giggs's importance
Netherlands boss Van Gaal will take over at Old Trafford on a three-year deal following this summer's World Cup in Brazil.
Januzaj, who made 34 appearances in all competitions during his breakthrough campaign at United last season, is excited about the club's prospects following a disappointing overall campaign.
"I feel very happy because he’s a great manager," he told reporters. "He's won a lot and I'm looking forward to working with him.
"I think we’re going to have a great future ahead so I’m looking forward to it."
Ryan Giggs was named temporary manager following the sacking of David Moyes in April, and will work alongside Van Gaal as No.2 from next season.
And Januzaj, named in Belgium's preliminary squad for the World Cup at just 19 years of age, praised Giggs for aiding in his development as a player.
"Every time I was playing on the pitch, I was asking Giggsy for advice on how to play and what to do on the pitch," he added.
"He helped me a lot. He was a great player and I have respect for him. It is very important to have someone like him at the club."