Williams became Stanford's highest-ranked recruit in the modern recruiting era and the program's first five-star recruit since Reid Travis in 2014. Williams played for the United States at the 2019 FIBA Under-19 Basketball World Cup in Heraklion, Greece. In seven games, he averaged 5.3 points and 1.2 assists per game, helping his team win the gold medal. Both of Williams' parents have served in the military: his mother, Marquita Fields-Williams, in the Army and Air Force, and his father, Ziaire Williams, in the Marine Corps. His mother is a probation officer, and his father works for 7 Up in Sylmar, Los Angeles.