It made music history at the ceremony in Los Angeles, winning best rap album.
The unsigned 23-year-old, whose real name is Chancelor Bennett, also won best new artist and best rap performance for No Problem.
"This is for every indie artist, everybody who has been doing this mixtape stuff for a long time," he said.
It's a huge rise for the artist, who's gone from releasing his first mixtape to Grammy-winner in five years.
"I didn't think I was going to get this one so I don't have cool stuff to say," he said after picking up best rap album.