Hasim Sharif Rahman is an American former professional boxer who competed from 1994 to 2014. He is a two-time world heavyweight champion, having held the unified WBC, IBF, IBO, and lineal titles in 2001; and the WBC title again from 2005 to 2006. Rahman first became known on the world stage in 2001 when he scored an upset knockout victory against Lennox Lewis to win the unified heavyweight championship.