[2] Pettersson made his Swedish Hockey League (SHL) debut playing with Skellefteå AIK during the 2013–14 season.[3] Pettersson began the 2017–18 season playing for the San Diego Gulls of the American Hockey League.[7] During the 2018–19 season, on 3 December 2018, Pettersson was traded by the Ducks to the Pittsburgh Penguins in exchange for Daniel Sprong.[16] On 31 January 2025, Pettersson was traded to the Vancouver Canucks along with forward Drew O'Connor, in exchange for forward Danton Heinen, defenceman Vincent Desharnais, right wing prospect Melvin Fernström and a conditional 2025 first-round pick.[17] On 9 May 2019, Pettersson was named to make his senior international debut with Sweden at the 2019 World Championships.