The Eagles had beaten Southampton, Stoke City, Tottenham Hotspur, Reading and Watford on the way to the showpiece, and now a repeat of the 1990 final awaited against Manchester United.
Connor Wickham had been the hero in the semi-final, heading home the winner against the Hornets to send Palace back to Wembley.
Alan Pardew, who played in that final 26 years earlier, was in the dugout on this occasion and led the side out to a raucous atmosphere. Tinie Tempah, Prince William and various other entertainment ebbed away, and, after Abide With Me, it was game on.
The match was a cagey one, and the Eagles took the lead with 12 minutes to go through Jason Puncheon, sparking wild celebrations in the crowd. United equalised three minutes later through Juan Mata, taking the game to extra time.
The game looked to be heading for penalties, after Chris Smalling’s red card, but Jesse Lingard scored the winner for United with 10 minutes to go to break Palace hearts.
Palace: Hennessey, Ward, Dann (Mariappa, 94), Delaney, Souare, Jedinak, McArthur, Zaha, Cabaye (Puncheon, 72), Bolasie, Wickham (Gayle, 86).
Man Utd: De Gea, Valencia, Smalling, Blind, Rojo (Darmian, 66), Carrick, Rooney, Mata (Lingard, 90), Fellaini, Martial, Rashford (Young, 72).