Riley turned professional in 1996 and spent time on the Nationwide Tour. He became a member of the PGA Tour in 1999 and made the top thirty on the money list in 2002 and 2003. His sole PGA Tour victory came at the 2002 Reno-Tahoe Open. He was a member of the losing 2004 United States Ryder Cup team and also played on a winning American team in that year's Tommy Bahama Challenge, which is an international match for pros aged 30 and under.