took part in local competitions. High school career Freshman season (2015–2016) In his freshman season, Ball started playing basketball for Chino Hills High School in Chino Hills, California. He was teammates with his two older brothers, Lonzo and LiAngelo, and his cousin, Andre Ball. In his first game, Ball scored 27 points as a starter. On March 5, 2016, he scored 26 points in a win over Sierra Canyon School for the CIF Southern Section Open Division title. Later in the month, Ball helped his team capture the CIF Open Division state championship, recording 14 points in the title game against De La Salle High School. Chino Hills finished the season with a 35–0 record and claimed the mythical national championship. Ball averaged 16.4 points and 3.8 assists per game and shared MaxPreps National Freshman of the Year honors with his teammate, Onyeka Okongwu. Sophomore season (2016–2017) On December 26, 2016, Ball made national headlines for making a half-court shot two seconds into a game. On February 4, 2017, he suffered his first high school loss despite scoring a game-high 36 points, with Oak Hill Academy ending Chino Hills' 60-game win streak. In his next game, on February 7, Ball scored 92 points in a win over Los Osos High School, the second-most single-game points in California high school history. He was criticized by analysts for cherry picking, as he often waited near half court to get an open shot on his next possession instead of defending. Ball finished the season averaging 26.7 points and almost 10 assists per game, earning MaxPreps Sophomore All-American first team recognition. On July 27, he featured in an AAU game against five-star recruit Zion Williamson that was featured in national sports media. On October 2, 2017, before his junior season, Ball left Chino Hills to be homeschooled because his father disapproved of newly-appointed head coach Dennis Latimore and school administration. On December 7, he signed with agent Harrison Gaines to play professionally overseas alongside his brother LiAngelo. The decision indicated that he would not play college basketball. In the following days, Gaines offered the brothers to professional teams in various European countries and in Japan. Senior season (2018–2019) On November 5, 2018, after skipping his junior year and a part of his senior year to play professionally, Ball joined SPIRE Institute and Academy, a prep school in Geneva, Ohio, where he played under head