The Aston Villa man is the creative hub of his club side, while he may get a chance to show his quality on the international stage with England at the European Championships.
Mourinho compared Grealish to Portugeuse legend Luis Figo.
Responding to Mourinho's comments, Grealish told talkSPORT: "I heard what Jose said, a lot of people sent me that.
"You try not to listen to too much, whether it's good or bad. It's always nice when people are speaking about you, especially someone like Jose Mourinho.
"He's done so much in the game, he's such a popular man in football and he's not short of football knowledge.
"Luis Figo is someone who I looked up to when I was a kid. He was an unbelievable player, but the the main thing was it came from Mourinho, who is an unbelievable manager.
"He's done unbelievable things in the game. Hopefully one day I could play under him."