He played college basketball for the Arizona Wildcats, where he was named a consensus second-team All-American and Pac-12 Player of the Year after his sophomore season.

[20] On July 8, he made his NBA Summer League debut, recording 23 points and four rebounds in a 96–84 win over the Charlotte Hornets.

[21] Ten days later, Mathurin was named to the All–NBA Summer League Second Team, averaging 19.3 points, 4 rebounds and 1.3 steals per game.

[22] On October 19, Mathurin made his regular season debut coming off the bench, recording 19 points in a 114–107 loss to the Washington Wizards.

[27] On October 29, Mathurin set a career high with 32 points on 6–of–9 three-point shooting, and five rebounds in a 125–116 win over the Brooklyn Nets.

[29] On December 1, Mathurin was named Eastern Conference Kia Rookie of the Month, averaging 19.2 points, 4 rebounds, on 40.3% three-point shooting.

[30] On January 31, 2023, Mathurin was named a 2023 NBA Rising Star alongside standout rookie teammate Andrew Nembhard.

[33][34] On March 28, as a starter against the Milwaukee Bucks, Mathurin recorded 29 points and a career-high 9 rebounds, while passing teammate Chris Duarte for most three-pointers made as a rookie in Pacers franchise history.

[38] On November 8, 2023, Mathurin recorded 22 points, 9 rebounds, 4 assists, 2 steals, along with 4 threes made in a win against the Utah Jazz.

[41] Mathurin played for Canada at the 2021 FIBA Under-19 World Cup in Riga and Daugavpils, Latvia after being cut from the Olympic team.

[43] One week later, Mathurin scored 31 points to lead Canada to a 101–92 victory over Serbia in the third–place game and win the bronze medal.