Léon Marchand is a French swimmer. He is the world record holder in the long course 400 metres individual medley and short course 200 metres individual medley; the Olympic record holder in the 200 metres butterfly, the 200 metres breaststroke, the 200 metres individual medley and the 400 metres individual medley; and the French record holder in the long course 200 metre individual medley, 200 metre butterfly and 200 metre breaststroke. At the 2024 Summer Olympics, he won gold medals in the 200 m medley, 200 metre breaststroke, 200 metre butterfly, and 400 metre medley. He became the fourth swimmer and third male swimmer in Olympic history to win four individual gold medals at a single Games.