Harold Warren Moon (born November 18, 1956) is an American former football quarterback who played professionally for 23 seasons. He spent the majority of his career with the Houston Oilers of the National Football League (NFL) and the Edmonton Eskimos of the Canadian Football League (CFL). Moon also played for the NFL's Minnesota Vikings, the Seattle Seahawks, and the Kansas City Chiefs. He is considered one of the greatest undrafted players in NFL history.