Remy LeBeau was adopted into the Thieves Guild of New Orleans as a young child. By the time he was a young adult he was considered one of the Guild's best and brightest. The leader of the Thieves Guild, Candra, joined forces with Apocalypse and became one of his Horsemen. This only marked her for attacks during the Horsemen's War of Succession and she was murdered by Holocaust.
Gambit fled and hid in the ruins of New Orleans. He found himself caught in the middle of a battle between Magneto's X-Men and a small band of Apocalypse's Infinite soldiers. Gambit could have slipped away quietly but he chose to help the X-Men and saved the life of Magneto, preventing Alex Summers from killing him with a plasma blast.
Magneto invited Gambit to join the X-Men and the two became close friends. Gambit began to have feelings for Rogue and considered asking her to marry him. On the day he planned to propose, Gambit saw Magneto and Rogue kiss. Moments later, an agent of Apocalypse named Wolverine attacked the X-Men. Both Gambit and Magneto were placed in grave danger and Rogue did not hesitate. She saved Magneto. Gambit was crushed. He left the X-Men and formed his own small band of thieves, the X-ternals. Gambit's new team stole from mutants and helped humans.
When Magneto discovered the possible existence of a better reality than the Age of Apocalypse, he summoned Gambit and asked him to steal the M'Kraan Crystal, the Nexus of all Realities. Gambit and his team, teleported by Gambit's girlfriend Lila Cheney, traveled to the Shi'ar Kingdom in search of the crystal.
Gambit was given a shard of the M'Kraan Crystal but in return had to give up a piece of his soul, his love for Rogue. The team teleported back to Earth and was betrayed by Strong Guy, a member of the X-ternals. Strong Guy took the shard of crystal from Gambit, kidnapped Magneto's child Charles, and delivered them both to Apocalypse. Gambit could have gone after him but chose to save an endangered Lila instead.
Gambit joined the X-Men in their fight at Apocalypse's capital. During the battle, Gambit killed an insane Colossus to prevent him from destroying the M'Kraan Crystal. Gambit and the rest of the X-Men were victorious over Apocalypse. Gambit has returned to the X-Men and fights alongside Magneto with new resolve.