John was impossible to defend as a high school basketball at Crenshaw and won the California State Mr. Basketball honor in both 1983 and 1984, while taking All-City honors both years. In 1984 he averaged 26.1 points per game under the great Willie West, and leading Crenshaw to the LA City Title. He was LA City Player of the Year, a Parade All-American and Mr. USA Basketball. He went to LSU for two seasons (1985-86) and finished as a collegiate All-American before entering the draft after his sophomore season.

He then was a first round NBA selection by Washington (12th overall). He had an eight-year NBA career and finished playing overseas in Spain. A great passer for a big man, Williams made the All-NBA Rookie Team in 1987. He later played in the NBA with the Los Angeles Clippers and Indiana Pacers, but injuries ended his NBA career in 1995. He continued overseas for several more seasons before retiring in 2002. He was inducted into the LA City Athletics HOF in 2015.