Smith was drafted 96th overall in the 2000 NFL Draft by the New Orleans Saints and appeared in fourteen games, including nine starts. He assumed the starting fullback role after being drafted and became one of the top blocking fullbacks in the league. He posted twenty-nine rushes for 131 yards and twelve receptions for 65 yards. He played all sixteen regular season games for the Saints during the 2002 season for the first time in his career, and helped bolster Deuce McAllister's rushing totals in 2003 thanks to his blocking.
Smith was signed by the Cleveland Browns as an unrestricted free agent on March 11, 2004 and played in all sixteen games of the 2004 season, including nine starts. He blocked for Lee Suggs' career-high 744-yard season. Smith went on to play in all sixteen games of the 2005 season (starting fifteen) and helped Reuben Droughns achieve the Browns' first thousand-yard season since the mid-1980s. On March 14th, 2007, the Browns announced the release of Smith. On March 23, 2007 he signed a two-year deal with the Cardinals.