Williams attended Auburn University after graduating from Etowah High School in Attalla, Alabama. He got the nickname "Cadillac" from a TV sportscaster in Alabama for the style and the way he ran – he was a notch above everyone on the field, and the name stuck.Mike Tirico, ESPN Monday Night Football, December 8, 2008 He began the 2001 season as a true freshman and the #3 running back on the depth chart. In the eighth game of the season he had a break-out game against the University of Arkansas and showed his outstanding talent and versatility as a running back. After amassing 177 yards in a 42–17 loss to Arkansas, Williams was promoted to starting running back. In the next game, the annual Deep South's Oldest Rivalry contest against the University of Georgia, he led Auburn to a 24–17 victory as he amassed 167 yards on a then Auburn record 41 carries, caught four passes for 71 yards and scored two touchdowns, one of which was the game winner. (That record stood until Tre Mason had 46 carries and 304 yards against Missouri in the 2013 SEC Championship Game.) Williams was injured early in the bitter in-state rivalry game against the University of Alabama (also known as the Iron Bowl) with a broken collar bone and had to sit out the rest of the season. In his freshman season, Williams played in nine games and finished with 614 yards on 120 carries (5.1 avg.) and six touchdowns.
