Despite his size, Williams was a highly skilled basketball player. He was in particular an exceptionally good passer, and averaged over 4 assists per game in 3 separate seasons, an excellent average for a player his size. He was frequently used as a point forward, handling the ball and conducting the offense.
As a rookie, Williams averaged just under ten points and five rebounds per game for the Bullets. He improved significantly his second season, and started 37 of 82 games. The 1988-89 NBA season, his third, was clearly his best, as he achieved career-high season totals in almost every statistical category, despite coming off the bench in all but one game.
Williams' productivity declined in the five injury-plagued seasons that followed. He missed more than half of four of those five seasons due to various injuries, which, though not necessarily caused by his weight, were certainly aggravated by it. His eight-year NBA career included five seasons with the Bullets, two with the Los Angeles Clippers, and one (his final season) with the Indiana Pacers. He left the NBA in 1995, but played yet for some years in the ACB league in Spain, with moderate individual success.