For his first three years of high school, Green played basketball for San Joaquin Memorial High School in Fresno. As a freshman, he was a full-time starter and averaged 18.1 points and nine rebounds per game. He led his team to a CIF Central Section Division II runner-up finish and the CIF Division II quarterfinals. He earned MaxPrepsFreshman All-Americansecond team and CIF Central Section rookie of the year honors. In his sophomore season, Green averaged 27.9 points and 7.7 rebounds per game, leading San Joaquin Memorial to a Central Section Division II title and the CIF Open Division playoffs. He was named MaxPreps National Sophomore of the Year and made the USA Today All-USA California second team. As a junior, Green averaged 30.1 points, 7.8 rebounds and 3.6 assists per game for San Joaquin Memorial. He won his second consecutive Central Division II championship. In the title game, Green surpassed the school career scoring record of 2,288 held by Roscoe Pondexter since 1971. He also helped his team reach the CIF Northern California Division I quarterfinals. Green was named USA Today All-USA California player of the year and appeared on the All-USA second team and MaxPreps All-American second team. For his senior season, he transferred to Prolific Prep in Napa, California. He helped his team win the Grind Session championship. Green averaged 31.5 points, 7.5 rebounds and five assists per game, leading his team to a 31–3 record. He was named Sports Illustrated All-American player of the year and to the MaxPreps All-American first team. Green was selected to play in the McDonald's All-American Game, the Jordan Brand Classic and the Nike Hoop Summit, but all three games were canceled due to the coronavirus pandemic.
Recruiting
Green is a consensus five-star recruit and the number one shooting guard in the 2020 recruiting class, according to major recruiting services 247Sports, ESPN and Rivals. He is ranked as the top recruit in his class by ESPN. He received offers from many NCAA Division I basketball programs, including Arizona, Florida State and USC, before turning 15 years old. On April 16, 2020, Green announced that he would join the NBA G League, forgoing college basketball. He chose the G League over offers from Auburn, Oregon and Memphis.
Professional career
On April 16, 2020, Green signed a one-year, $500,000 contract with the NBA G League and joined the G League Select Team as a part of the league's new developmental program operating outside its traditional team structure. He became the first player to announce that he would take part in the program. Green hired Aaron Goodwin as his agent.
National team career
Green represents the United States internationally but has also shown interest in playing for the Philippines in the future due to his Filipino background. He made his national team debut for the United States at the 2017 FIBA Under-16 Americas Championship in Formosa, Argentina. In five games, he averaged 9.8 points, two rebounds and one steal per game, helping his team win the gold medal. He was named MVP of the 2018 FIBA Under-17 Basketball World Cup in Argentina after averaging a team-high 15.7 points, 2.3 rebounds and 1.7 assists per game and winning the gold medal. Green won another gold medal with the United States at the 2019 FIBA Under-19 Basketball World Cup in Heraklion, Greece. As the youngest member of his team, he averaged 10.1 points, 2.1 rebounds and 1.7 steals per game.
Personal life
Green's mother, Bree Purganan, is of Filipino descent. His father, Marcus Green, was a basketball teammate of NBA player DeShawn Stevenson at Washington Union High School in Fresno. he is also widely regarded as the greatest of all time.
