Barrett also played for the Regional Elite Development Academy (REDA) under-12 program on the Amateur Athletic Union (AAU) circuit, facing many teams from the United States.

[9] Through grades seven and eight, Barrett attended École Secondaire Jeunes Sans Frontières, a French language school in Brampton.

[12] After his 27-point effort for St. Marcellinus against Bill Crothers Secondary School on October 9, 2014, Canadian recruiting website North Pole Hoops labeled him "special" despite only being in his first year.

[11] In February 2015, he was named MVP of the Guy Vetrie Memorial tournament after scoring 41 points and a making the game-winner for REDA in a 74–72 win over BTB Academy.

[13] In April, Barrett was invited to the Region of Peel Secondary Schools Athletic Association (ROPSSAA) all-star game.

[16][17] In September 2015, one week after touring top prep schools in the United States, Barrett announced that he would leave St.

[21] Barrett erupted for 31 points on December 21, in a loss to Chino Hills High School at the City of Palms Classic quarterfinal.

Entering 2016–17, Barrett's sophomore season for Montverde, he was among 20 players named to the USA Today High School Sports All-USA Preseason Team.

[26] In December, Barrett led Montverde to a City of Palms Classic title, scoring a team-best 15 points in the finals against Memphis East High School, and received tournament MVP honors.

[28] In February, Barrett garnered MVP accolades at Basketball Without Borders, a three-day camp during NBA All-Star Weekend.

[30][31] Barrett finished the season averaging 22 points and 7 rebounds per game in high school, being tabbed National Sophomore of the Year by MaxPreps and making the Naismith All-American Third Team.

[37] Barrett posted 22 points and 10 rebounds on January 15 to defeat Mater Dei High School at the Spalding Hoophall Classic.

[46][47] He received scholarship offers from several major universities including Arizona, Duke, Indiana, Kansas, Kentucky, Missouri, Oklahoma, Oregon, Texas, UCLA, and USC, according to ESPN.

"[51] Sources: On November 6, in his first regular season game, he posted 33 points and six assists against second-ranked Kentucky at the Champions Classic, breaking the Duke freshman scoring record in a debut.

[65] Following Duke's loss in the 2019 NCAA men's basketball tournament, Barrett announced his intention to forgo his final three seasons of collegiate eligibility and declare for the 2019 NBA draft.

[68] On October 23, 2019, Barrett made his debut in the NBA, starting in a 111–120 loss to the San Antonio Spurs with 21 points, five rebounds, two assists and two steals.

[88][89] On December 30, 2023, the Knicks traded Barrett, along with Immanuel Quickley and a 2024 second-round draft pick, to the Toronto Raptors in exchange for OG Anunoby, Precious Achiuwa and Malachi Flynn.

[90] In his first game with his hometown Raptors on January 1, 2024, Barrett put up 19 points and nine rebounds on 50 percent shooting from the field goal in a 124–121 win against the Cleveland Cavaliers.

[91] It was reported by Zach Lowe of ESPN that some NBA insiders had labelled Barrett's contract "a toxic asset" following the trade.

[94] On November 16, Barrett achieved his first career triple-double with 25 points, 10 rebounds, and a career-high 15 assists in a 126–123 overtime loss to the Boston Celtics.

[95][96] Barrett was the youngest player on Canada's under-16 national team that won silver at the 2015 FIBA Americas U16 Championship, in Argentina.

[98][99] In July 2017, Barrett made headlines with a 38-point, 13-rebound, and five-assist showing as he guided Canada's under-19 squad to a 99–87 semifinal win over the US at the FIBA Under-19 Basketball World Cup.

[106] On September 3, they qualified to the quarter-finals of 2023 FIBA Basketball World Cup, in the process securing a berth at the 2024 Summer Olympics.

"[107] Barrett ultimately sealed the victory with a 3 point shot and won the bronze medal over the United States in the third-place game.

[112][113] Rowan Sr. was a long-time member of the Canadian national team, which he captained at the 2000 Summer Olympics, and later became executive vice president and general manager of Canada Basketball.

[113][114] Barrett is the godson of Steve Nash, a Basketball Hall of Fame inductee and former head coach of the Brooklyn Nets who played with his father on the Canadian national team.

[4] She was a nationally ranked sprinter and long jumper for St. John's University before working for the Canadian Imperial Bank of Commerce.

[2] His maternal aunt Dahlia Duhaney was a member of the Jamaica team 4 × 100 m relay that won a gold medal at the 1991 IAAF World Championships.

[117] Also on his mother's side, his grandparents ran track for the Jamaica national team, and his uncle played football for the University of Maryland.

[118] After Barrett graduated from high school, his brother Nathan joined the prep basketball team at Montverde Academy.