Sheezel, who was already signed until the end of 2024, was the prized No.3 pick at last year's national draft.
But his stock has risen even more following his 34-disposal display in last week's five-point win over West Coast.
Sheezel was a rock across half-back, and his 631 metres gained showed the attacking weapon he can be.
The new deal will run until the end of 2026, with the Kangaroos excited about the 18-year-old's potential progression.
"We are thrilled to have both a player and person of Harry's calibre commit to the club for a further two years," North Melbourne head of talent Brady Rawlings said in a statement.
"Harry is clearly an exciting talent and has shown the potential to play several roles for the club, whether it's up forward, in the midfield or off half-back.
"His debut against the Eagles was only a small preview of what Harry has to offer, and we look forward to seeing what more he is capable of as he gets more games under his belt."
The Kangaroos, wooden spooners in the past two seasons, will be aiming to make it two wins on the trot when they take on Fremantle at Optus Stadium on Saturday.
The match will pit North Melbourne recruit Griffin Logue against his former side.
Logue played 64 games across six seasons at the Dockers before moving to the Kangaroos at the end of last year.
