Van Gaal - who has managed Bayern Munich, Barcelona and Ajax Amsterdam - will take over the United reins after guiding Netherlands at the ongoing World Cup in Brazil.
"He has won everything as a coach," De Gea said of Van Gaal in an interview with Marca.
"He's a very good coach and I think he's going to bring a lot to Manchester United, important and innovative ideas and I think he's going to be very good for us."
Van Gaal's predecessor David Moyes was criticised for his negative tactics in a poor nine-month spell with the English giants. De Gea is hopeful Van Gaal can inspire a different brand of football.
"He's going to help us a lot because he's going to bring a different style of play," he added.
De Gea's Spain will face Holland tonight in a much-anticipated Group B opener in Brazil. De Gea is La Roja's third-choice keeper behind Iker Casillas and Pepe Reina.