Derby County will contest the play-off final with Aston Villa after an incredible semi-final, second leg at Elland Road on Wednesday night.
Trailing by a goal going into the game after Saturday's first leg, the Rams fell further behind early on but recovered superbly with goals either side of half-time proving crucial and sub Jack Marriott scoring his first goals since January.
And it all means they are 90 minutes away from a return to the Premier League.
Derby began well and Harry Wilson fired over after Mason Mount's shot had been blocked, Wilson fouled in the process but Mount's free-kick deflected away from danger.
Luke Ayling put a difficult chance over the top from Mateusz Klich's cross on the quarter hour, but nine minutes later their lead arrived.
A free-kick out wide from Kalvin Phillips somehow evaded everyone and struck the far post, Stuart Dallas on hand to turn in the rebound from a couple of yards out and double Leeds' overall advantage.
It was nearly trebled six minutes later when Klich's 25-yarder took a big deflection off Richard Keogh's head and struck the crossbar before the ball was cleared.
Patrick Bamford then broke forward but shot weakly at Kelle Roos, not long after being booked for diving when challenged in the penalty area.
Derby nearly pulled one back three minutes before the break when Mason Bennett's looping header following a corner came back off the post and Leeds cleared, before the Rams brought Marriott into the fray to replace Duane Holmes in order to give them more firepower.
And it paid dividends within seconds. A total mix-up between defender Liam Cooper and keeper Kiko Casilla allowed the ball to run free and Marriott, with his first touch, was able to roll the ball into the net on the stroke of half-time.
Moments into the second-half, the Rams were level on aggregate.
An immediate break forward by Keogh saw him find Wilson, who in turn slipped the ball to Mount and despite being clipped he was able to scoop the ball home from around 12 yards out.
Leeds were all over the place at the back and Mount forced Casilla into a save low down four minutes later, the hosts then responding with Jack Harrison's shot being blocked by Keogh.
Dallas and Pablo Hernandez then saw efforts blocked first by Roos and then a diving Malone respectively, before the Rams were handed the golden chance of a third.
Cooper blatantly pulled back Bennett as he chased a ball into the penalty area, Wilson stepping up to confidently slot the ball home and give Derby the lead for the first time in the tie.
It didn't last long. Leeds responded well and after a good move down the left, Dallas, who replays showed was marginally offside, cut in on 62 minutes to place a low effort into the far corner of the net for his and Leeds' second and the tie was level again.
Then Luke Ayling broke into the box but lost his footing and mis-cued his shot wide of the target as the pulsating clash continued to be open and exciting.
With several bookings having littered the game, there was an air of inevitability one would turn to red and that was the case on 78 minutes when Gaetano Berardi went in carelessly on Bradley Johnson and having been booked earlier on, he was sent off, although his challenge could well have warranted a straight red anyway.
The Rams were so close to going in front on 85 minutes when Wilson stroked an effort against the post, but seconds later they did get their fourth when great work by Keogh saw him work with Mount and then find Marriott who deposited a fine dinked finish into the corner of the net.
Leeds put the pressure on in response, Dallas forcing Roos to push a curler away as the game entered five minutes of stoppage time, then the second red card came when Malone dived in on Hernandez and was shown his second yellow, meaning he will miss the final.
But it mattered not, as the final whistle soon blew to confirm Derby's trip to Wembley on May 27.
Leeds: Casilla, Ayling, Cooper (c), Bamford (Brown 88), Dallas, Hernandez, Harrison, Phillips, Berardi, Klich (Clarke 86), Shackleton.
Subs not used: Peacock-Farrell, Jansson, Strujk, Gotts, Bogusz
Derby: Roos, Tomori, Keogh (c), Wilson (Cole 90+3), Mount, Lawrence, Johnson, Bennett (Huddlestone 59), Holmes (Marriott 44), Bogle, Malone
Subs not used: Carson, Jozefzoon, Evans, Knight