Dorsey initially attended Ribét Academy in his freshman season. He then transferred to St. John Bosco High School, in Bellflower, California. In his sophomore season, he began to establish himself as a solid scorer, with a 17.0 points-per-game scoring average. He made a big impact afterwards, where, as a junior, he managed to help his team win the state championship, and was the star of the team, averaging 21.4 points per game, 6.0 rebounds, and 4.7 assists per game. In his senior year, he decided to transfer to Maranatha, due to his desire to return to his hometown of Pasadena. He was a standout player there, where he dazzled with his scoring and athletic abilities. He averaged 34.0 points per game, to go along with 10.4 rebounds, 3.7 assists, and 1.9 steals per game. Together with his second state championship win, he earned the 2015 Gatorade State Player of the Year for California award. He had many impressive games, like the one where he scored 52 points, in an 85–60 win. He was able to be efficient in every game, shown by the fact that he finished in double figures in scoring all 30 of his games played. Despite being considered the 23rd-best player of his age group, he was not selected to play in the McDonald's All-American Game. He initially committed to play college basketball at the University of Arizona, but he changed his mind, and then committed to Oregon, instead, on February 2, 2015.
College career
Freshman year
Dorsey played his first official game as an Oregon Duck, in the season opener against Jackson State, where Oregon won; and he was declared the MVP of the game, after scoring 20 points for his team, in an 80–52 win. Dorsey missed two games in the middle of the season, due to an injury, but he soon came back into form. He scored a career-high 25 points against rivals Oregon State, in a 91–81 win. The Ducks won the Pac-12regular season and 2016 Conference Tournament. In the tournament final against the University Of Utah, Dorsey's team, Oregon, dominated, and beat Utah by a score of 88–57. Oregon's 31-point margin of victory was the largest in the Pac-12 Championship game's history. Dorsey had a stellar performance, being the top scorer, with 23 points, and having also grabbed 9 rebounds. He was picked for the All-Tournament Team, and was the tournament's top scorer. Oregon earned the top seed in the West region, and went as the number one team of their conference into March Madness. After the season, Dorsey was one out of 162 early-entry candidates that initially declared for the 2016 NBA draft. However, he ultimately withdrew before the draft withdrawal deadline.
Dorsey was selected by the Atlanta Hawks, in the 2nd round of the 2017 NBA draft, with 41st overall pick of the draft. He then signed a 2-year contract with the Hawks. On November 12, 2017, Dorsey was sent by Atlanta to the Erie BayHawks, of the NBA G-League, on assignment.
On February 7, 2019, Dorsey was traded to the Memphis Grizzlies in exchange for Shelvin Mack. He was assigned to the Memphis Hustle on February 8 and made his debut that evening. By the end of the 2018-19 season, Dorsey was regularly playing crunch-time minutes for the Grizzlies.
Maccabi Tel Aviv (2019–present)
On August 17, 2019, Dorsey joined Maccabi Tel Aviv of the Israeli Premier League and the EuroLeague, signing a one-year deal with an option for another one. On November 1, 2019, Dorsey recorded a EuroLeague career-high 19 points, shooting 7-of-12 from the field, along with four rebounds, three assists and two steals in a 90–65 win over Olympiacos.
On June 6, 2016, Dorsey was named to the senior men's Greek national basketball team's 16-man preliminary training camp roster for the 2016 Turin FIBA World Olympic Qualifying Tournament. He played with the senior team in 3 friendly games, however, he did not make the actual 12-man roster that would compete at the tournament. He played with Greece at the 2019 FIBA World Cup qualification.
Dorsey was born to an African-American father and a Greek mother. He acquired dual citizenship and a Greek passport, due to his mother's Greek background. Dorsey's mother was born to a Greek father, under the Greek surname Konstantinidou.
