During his collegiate tenure at Illinois, Williams was a formidable force, contributing significantly from his freshman year (200203) where he started 30 of 32 games and ranked third in the Big Ten with 4.53 assists per game. Under coach Bruce Weber, his sophomore year saw his scoring average climb to 14.0 points and assists to 6.17 per game, earning him First-Team All-Big Ten honors. His exceptional junior season culminated in consensus Second Team All-American, First Team All-Big Ten, Big Ten All-Tournament Team, All-Final Four team accolades, and being named the University of Illinois Athlete of the Year. Following his standout collegiate career, Williams was selected third overall by the Utah Jazz in the 2005 NBA draft, quickly making an impact by earning a spot on the NBA All-Rookie First Team in 2006.
Post-basketball, he has explored new avenues, transitioning into combat sports. In 2021, Williams notably competed in and won an exhibition boxing match, further showcasing his versatility and competitive spirit beyond the basketball court.