Murphy attended college at the University of Idaho. In 1992 he was signed by the British Columbia Lions where he won the 1994 Grey Cup. Between 1995 and 1999 he played for the Scottish Claymores of NFL Europe. In 1996 he was named World Bowl MVP. In 1999 he would play for the Tampa Bay Buccaneers and the Minnesota Vikings of the National Football League. In 2001 he played for the Las Vegas Outlaws of the XFL and the St. Louis Rams of the NFL where he went on to play in the Super Bowl. He signed with the Ottawa Renegades in 2003. He went undrafted in the 2006 CFL Dispersal Draft after the suspension of the Renegades' franchise, but signed with the Saskatchewan Roughriders in September 2006. He culminated his career as a member of the Riders' Grey Cup winning team in 2007. On November 28, 2007, it was announced that Murphy had retired from professional football. Murphy is the only player ever to play in the CFL, NFL, XFL and NFL Europe. Murphy is also the only player to suit up for the Super Bowl, Grey Cup and World Bowl contests.