Born in Yugoslavia, Semir Pepic competed for the Slovak Republic at the 1996 Atlanta Olympic Games. Pepic missed selection for the 2000 Olympic Games due to injury, but travelled to Sydney as a sparring partner for a fellow competitor. Pepic decided to move to Australia permanently in 2002 and received citizenship in 2003. Pepic competed for Australia at the 2004 Athens Olympics where he placed ninth in the heavyweight division. Pepic also competed for Australia at the 2008 Olympic Games and lost in the opening round.