[2][3] As a youth, he played for the local Skuru IK basketball team before moving north at age 16 to join BC Luleå.

[4] He played two seasons with RIG Luleå and BC Luleå in the Swedish Basketball League, being named the league's star of the year in his first season at the top level with averages of 7.6 points, 2.8 rebounds, 1.9 assists and 0.8 steals per game.

[10] He initially entered the 2023 NBA draft but later announced he was returning to Arizona for his senior year in 2023–24.

[12] On July 2, he signed with Miami[13] and on 23 October 2024, he made his NBA debut in a 116–97 loss to the Orlando Magic, scoring 2 points.

[15] Larsson has represented Sweden at the under-16, under-18, and senior levels, including averaging 6.3 points in 2023 FIBA Basketball World Cup qualifiers.