Unger Sörum made his professional debut for
Leksands IF of the
Swedish Hockey League (SHL) during
2022–23 season where he appeared in seven games. He spent the majority of the season with Leksands IF's
under-20 team, where he recorded ten goals and 36 assists in 42 regular season games. His 36 assists tied for the team lead. During the
Anton Cup playoffs he recorded four goals and five assists in seven games, finishing second on the team in points and tied for first in goals during the postseason. Unger Sörum was drafted in the second round, 62nd overall, by the
Carolina Hurricanes in the
2023 NHL entry draft. He was the youngest member of his draft class at 17 years old. On 15 July 2023, the Hurricanes signed Unger Sörum to a three-year, entry-level contract. During preseason training camp for the
2023–24 NHL season, he challenged for a roster spot, and was one of the final players cut. After not making the Hurricanes' roster, he was reassigned to Leksands IF for the
2023–24 SHL season. During his first full professional year, he recorded three goals and 12 assists in 35 regular season games and one goal and two assists in six playoff games. ==International play==