Jean-Paul DuChamp was once involved with Isabelle Kristel, who was secretly an agent for DGSE intelligence. When Kristel broke off their relationship, DuChamp joined the French Foreign Legion, and ultimately became a soldier of fortune in order to forget about her. While operating in Africa, he befriended fellow mercenary Marc Spector, who nicknamed him "Frenchie". Jean-Paul served mainly as a pilot on his assignments, and he and Spector eventually found work alongside Raoul Bushman. When Bushman led a raid on Selima, Egypt, intending to loot Dr. Peter Alraune, Sr's archaeological dig of the Tomb of King Sety II, Spector turned against Bushman for murdering Dr. Alraune. Bushman left Spector in the desert to die, but Spector was seemingly brought back to life by the Egyptian god Khonshu, and he became Khonshu's instrument of vengeance. Jean-Paul helped Spector attack Bushman's forces that evening. Jean-Paul and Peter's daughter Marlene Alraune became Spector's trusted confidants while Spector adopted a costumed identity as Moon Knight and became a New York-based crime fighter. Jean-Paul designed and piloted Moon Knight's personal aircraft, the Mooncopter.
Seeking to spy on the crime cartel the Committee, Spector had Jean-Paul infiltrate their ranks as "Monsieur LeBlanc". Exploiting Moon Knight's obscurity, "LeBlanc" arranged for the Committee to "create" Moon Knight as their own agent, and hired Spector to capture the Werewolf (Jack Russell) for them. Moon Knight played along with the Committee, but ultimately released Russell from their captivity. Jean-Paul continued to spy upon the Committee until Moon Knight finally dismantled the organization. Jean-Paul was eventually reunited with Isabelle Kristel, but she was killed on assignment by Cajun Creed, and Jean-Paul helped Moon Knight capture Creed.
Jean-Paul aided Moon Knight in many adventures, even after the criminal Killer Shrike nearly killed him by crashing the Mooncopter; however, when Moon Knight's brother Randall Spector set off an explosion at Spector Manor, Jean-Paul's legs were crushed by debris, and he was crippled. Jean-Paul continued to assist Moon Knight, but his injuries made piloting an infrequent task. Jean-Paul's then girlfriend Chloe Tran revealed herself to be a member of the Knights Templar, an ancient order engaged in a centuries-long conflict with the Hellbent, a race of supernatural creatures. Chloe informed Jean-Paul that he was the Bloodline, and possessed a post-hypnotic ability to transform into any of his ancestors through concentration. As Bloodline, Jean-Paul helped Moon Knight combat the Hellbent, but Moon Knight seemingly died in battle with Hellbent leader Seth Phalkon.
Khonshu resurrected Moon Knight again, and Jean-Paul served as his pilot; however, after breaking his own legs in a vicious fight with Bushman, Spector became indignant toward his friends and drove Jean-Paul away. Embracing his long-concealed homosexuality, Jean-Paul became involved with Rob Silverman, opening the restaurant "En Table" with him. When a new Committee sought revenge on Spector for the earlier organization's defeat, they had an agent give DuChamp a terrible beating; however, they miscalculated the effect this would have on Spector who resumed his Moon Knight guise to destroy the new Committee. Jean-Paul remains Moon Knight's ally, but offered up Spector's young long-time associate Ray Landers to serve as his new pilot. Rob currently serves as Spector's physical therapist.