Roaf received an athletic scholarship to attend Louisiana Tech University, where he had an outstanding career for the Louisiana Tech Bulldogs football team from 1989 to 1992. Known for his blocking ability and his considerable speed for his size, he was recognized as a consensus first-team All-American, and was also a finalist in his senior year for the Outland Trophy for the best offensive lineman in college.
He began his professional football career with the NFL's New Orleans Saints, who drafted him with the eighth pick of the first round in the 1993 draft. The draft pick was acquired from the Detroit Lions for the rights to Pat Swilling. Roaf played nine seasons for the Saints; he was named to seven Pro Bowls, and won a spot on both the NFL 1990s All-Decade Team and the 2000s All-Decade Team, making him the most awarded player in Saints history. Roaf suffered a season-ending injury in 2001 and then was traded to the Kansas City Chiefs in March 2002 for a conditional draft choice. He played four more seasons with the Chiefs, and was selected for the Pro Bowl in each of those four years, for a total of 11 Pro Bowl selections. His election to the Pro Football Hall of Fame was announced on February 4, 2012.
Roaf has been elected to sports halls of fame for Arkansas (in 2007), Louisiana (in 2009), and the New Orleans Saints (in 2008). He was elected to the Pro Football Hall of Fame on February 4, 2012, in his second year of eligibility.