Leeds' fourth Friday night win in a row lifted them to 16th, nine points clear of the drop zone and equal on points with the two clubs above them, Crystal Palace and Tottenham Hotspur (both 29).
Forest's four-game unbeaten league run came to an unceremonious end and they remain in 17th place on 26 points, only above West Ham United, Burnley and Wolverhampton Wanderers.
Leeds started the better side and led after 26 minutes.
With the Forest defence static, Jayden Bogle ran on to a superb through ball from Ilia Gruev and poked it under the hesitant keeper.
Four minutes later, Noah Okafor broke a 16-game scoring drought to make it 2-0. But much the credit went to James Justin, who started the move on the right flank and saw his shot parried into the path of the former Napoli and AC Milan winger who made no mistake.
Dominic Calvert-Lewin completed the scoring three minutes into the second half when he dived to chest Gruev's ball into the box past Stefan Ortega.
Lorenzo Lucca's consolation goal for Forest with six minutes remaining did little to dampen the enthusiasm of the home fans at Elland Road.
"It is always nice to take the three points back to the training ground," Justin said.
"We deserved them, we put in the graft.
"Some of the football we played tonight was some of the best we've played all season. To put in a performance like that is a big one in the league."
