Larsson left his hometown team IF Troja-Ljungby in 2013 to join Frolunda in the Swedish Hockey League and was selected by the Anaheim Ducks in the first round (No. 27) of the 2015 NHL Draft. He signed a two-year contract with Frolunda and helped it win the SHL title in 2016.
After the season, Larsson signed an amateur tryout contract with San Diego of the American Hockey League on April 28, 2016. He was given a three-year, entry-level contract by the Ducks on May 20, 2016 and made his NHL debut against the Dallas Stars on Oct. 13. He returned to Frolunda on loan Nov. 2 and played there for the remainder of the season.