As a 6'8" small forward from the University of Notre Dame, Williams was an honorable mention All-American, averaging 22.4 points and 8.4 rebounds during his senior season. Williams was an NBA first-round pick despite a pre-existing heart condition. He was selected by the New York Knicks in the first round (24th overall) of the 1994 NBA Draft. Williams played in 9 NBA seasons from 1994 to 2003. He played for the Knicks, San Antonio Spurs, Denver Nuggets, Orlando Magic and Philadelphia 76ers.
In his NBA career, Williams played in 456 games, scored a total of 2,884 points and averaged 6.3 points-per-game. On April 8, 1997, he scored a career high 30 points as a member of the Spurs against the Denver Nuggets. Chronic knee problems forced him into retirement in 2003.
In 2005, Williams won an NBA championship as a coaching staff intern with the San Antonio Spurs. In 2005, Williams was hired by new head coach Nate McMillan as an assistant coach for the Portland Trail Blazers. On June 7, 2010, Williams was offered a three-year contract to be the head coach of the New Orleans Hornets. As of the date hired, Williams became the youngest head coach in the NBA at 38 years old.
On August 18, 2012, Williams accepted a four-year contract extension from the New Orleans Pelicans (before Hornets). On June 9, 2013, Williams accepted an assistant coach role with USA Basketball, along with Jim Boeheim and Tom Thibodeau, for the run to the 2016 Olympics in Rio de Janeiro, Brazil.