Gelhardt, 20, who enjoyed an outstanding breakthrough season last term, has committed his future at Elland Road until the summer of 2027.
The former Wigan Athletic player featured 22 times for the first team in the 2021-22 campaign, scoring two goals at Premier League level.
United have also secured the futures of two other rising stars in the shape of forward Sam Greenwood and winger Crysencio Summerville, who have signed contracts until June 2026.
The trio's extended deals at Elland Road are a welcome boost ahead of the 2022-23 Premier League campaign, which gets underway when Arsenal take on Crystal Palace at Selhurst Park on Friday night.
Leeds are in action against Wolves on Saturday, after a summer of change at the club under Jesse Marsch. Kalvin Phillips and Raphinha have both departed but the Whites have reinvested the fees generated from those sales and spent close to £100m on new arrivals this window.
Ahead of the upcoming campaign, data experts at FiveThirtyEight have crunched the numbers to give every team's probability of winning the league, being promoted and being relegated.
With an explanation of how the model works HERE, here's where data experts are tipping every team to finish and how many points they will get in the Premier League next season...