England Under-18 international Bali Mumba has signed his first professional deal with Sunderland.
The 17-year-old midfielder, who has been with the Black Cats since the age of eight, will remain with the club until the summer of 2021.
He made his first-team debut in the Championship last season and has gone on to feature three times in League One so far this term.
"It is what I have been dreaming about since I was a kid," Mumba said.
"All the hard work is beginning to pay off and my family and I are all buzzing about it."
Sunderland manager Jack Ross said the club is "delighted" to ensure that one of the clubs "best" and "most promising" players remains at the Stadium of Light.
"He is undoubtedly someone who will attract attention throughout the country because of his ability but, hopefully, it is a real statement of our intent about how we want to move the club forward," Ross said.