Green was born and grew up in Petersburg, Virginia, until he was 12 years old, when he moved in to live with his aunt in Alberta, Virginia. He attended Brunswick High School in nearby Lawrenceville, where he played basketball for former Virginia and NBA shooting guard Bryant Stith. As a senior, Green averaged averaged 18.6 points, 5.8 rebounds, 2.3 assists and 3.1 steals per game and led the Bulldogs to the VHSL Group AA Division 3 state title. He was named first team All-State and the Virginia Co-Player of the Year. He committed to play college basketball at Radford University, the only NCAA Division I school to offer him a scholarship. Green also played football at Brunswick and was the team's starting quarterback during his junior and senior years. Green was offered a scholarship to James Madison University to play football.
College career
Green played for four seasons as a member of the Radford Highlanders. Green entered the starting lineup as a freshman, averaging 10.2 points, 6.7 rebounds and 1.4 steals per game and was named to the Big South Conference's All-Newcomer team. As a sophomore, his first full season as a starter, Green led the Highlanders with 14.6 points and 8.1 rebounds per game and was named Second Team All-Big South. He was named First Team All-Big South after averaged 16.9 points, 8.1 rebounds and 1.9 steals per game while setting the school single season record for steals with 68 in his junior season. As a senior, Green averaged 15.4 points, nine rebounds, and 1.9 steals and was again named First Team All-Big South as well as the conference Defensive Player of the Year. Green finished his collegiate career as Radford's career leader in rebounds, steals, and games played and second all-time in scoring with 1,911 points.
Professional career
Peixegalego
After garnering little NBA interest, Green signed with CB Marín Peixegalego of the Spanish third division, LEB Plata on September 11, 2015. In his first professional season, Green averaged 18 points, 6.7 rebounds, and 2.2 steals per game and was named the LEB Plata's Most Valuable Player.
Trieste
Green signed with Pallacanestro Trieste of the Italian second division, Serie A2 Basket, on July 11, 2016. He averaged 15.6 points, 5.5 rebounds, and 2.4 steals in 45 games with Trieste during the 2016-17 season. He returned to Trieste for a second season, averaging 18.1 points, 7.1 rebounds, 1.4 assists and a league-leading 2.3 steals per game. Following the season, Green was named to the Phoenix SunsNBA Summer League roster.
Green signed with ratiopharm Ulm of the Basketball Bundesliga on July 25, 2018. Green averaged 13.8 points, 4.7 rebounds, 1.6 assists, and 2.3 steals per game in 51 games between league and EuroCup play. He was selected as a reserve to play in the 2019 BBL All-Star Game as a member of the "International" team.
Boston Celtics
Green was invited to play in the 2019 NBA Summer League as a member of the Boston Celtics roster. He played in all five of the Celtics' games and averaged 10.8 points, 4.8 rebounds, 2.8 assists, and 1.8 steals. The Celtics signed Green to a two year contract with a partially guaranteed salary for the first season. After averaging 9.3 points and 4.0 rebounds in 14.1 minutes played per game in the preseason, Green was named to the Celtics final roster going into the 2019-20 season. Green made his NBA debut on October 25, 2019 against the Toronto Raptors, playing the last five seconds of the first half as a defensive replacement in a 112-106 win. The appearance made him the first former Radford player to play in an NBA game. Green scored his first career points on November 7, 2019 against the Charlotte Hornets, finishing the game with 12 points on 5-of-9 shooting in a 108-87 win. Green made his first NBA start on February 3, 2020 against the Atlanta Hawks, grabbing 3 rebounds with 1 assist and no points in 18 minutes played.
