The 18-year-old made his league debut in Leeds 1-0 win over Wolverhampton Wanderers at the weekend, and the right-back is delighted to have committed his immediate future to the club.
Byram told the club's official website: "I'm delighted. I didn't expect anything like this when we came back for pre-season training.
"The manager and the staff have been really encouraging."
Byram could retain his place in the starting lineup when Leeds travel to Blackpool this evening.