Léon Marchand is a French swimmer. He is the World record holder in the long course 200 and 400 metres individual medley, and in the short course 200 metres individual medley; the Olympic record holder in the 200 and 400 metres individual medley, 200 metres butterfly and the 200 metres breaststroke; the European record holder in the long course 200 and 400 metres individual medley and the 200 meters breaststroke, in the short course 100 and 200 metres individual medley and the French record holder in the long course 200 and 400 metres individual medley, 200 metres butterfly and the 200 metres breaststroke, and in the short course 100, 200, 400 metres individual medley and the 200 metres 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.