The teenage midfielder played 78 minutes for the Blades' under-23s in their 2-2 with Wigan Athletic.
He also appeared as a substitute in a victory over Barnsley the previous week.
The Barnsley-born player signed his first professional contract in the summer, a three-year deal, but is yet to make a first-team appearance.
Leak-Blunt has been with at Leeds's academy since the age of eight, and his father, former Whites midfielder Jason Blunt, coached there until two years ago.
“I’ve been at the club a long time now and to sign my first professional contract is a great feeling", Leak-Blunt told Leeds's official website at the time.
“It’s good to progress as a young player coming through the ranks, so I hope I can get off to a good start as a pro.”
Head coach Marcelo Bielsa has given debuts to a number of young players, but admits the club need to do more.
“You can see a lot of young players appearing in English football at the moment, and the processes are idea,” he said recently. “It's not about there being a correct way but everyone should take a look and try to learn from it.
“Izzy Brown (now on loan at Luton Town) suffered when he was here with us and lost a bit of self-esteem. He found the process worrying.
“When we were working with him we gave him all our attention and tried to improve him. That made us think about our methods and our ability.
“If a players like him has success at Luton but not with us, we have to learn from it because Luton's coaching staff achieved something we couldn't.
“When Izzy Brown was with us he had the feeling we were ignoring him and we couldn't improve him as a player. After what he said, we know there are other players who think similarly to him.
“But they will support our methods if they can see them being a success.”
If Leak-Blunt is to be a success, it looks like he may have to move elsewhere.