The Chicago Blackhawks did not offer Stjernborg an entry-level contract as of June 1, 2025; the draft rights of their 2021 fourth-round pick (108th overall) have expired. Stjernborg will play for Skelleftea AIK of the Swedish Hockey League during the 2025-26 season.

Stjernborg was selected in the fourth round, 108th overall, by the Chicago Blackhawks in the 2021 NHL Draft.

Stjernborg is an interesting prospect who plays with a high level of effort and a steady two-way game. The young Swede is a good skater who has a good top speed but his quickness and agility are where he makes his money. He is a relentless forechecker, utilizing sed agility to get in on a battle and come away from it with the puck and room to roam. He is still a bit immature physically, but he still gives opponents fits in board battles. He never stops working and his feet always seem to be moving. There are a few instances of becoming stagnant at the net-front but there are worse places to settle down. He gets himself into a good body position using his smaller stature and thick build to get under his opponents and frame out to protect or collect the puck. His playmaking ability is fairly simplistic but he is very good at making the play that he is presented with by his opposition. He is a crafty player down low and finds a way to get the puck on net even when seemingly buried in a crowd in front. He has good hand-eye and works the net-front well when he is there. Defensively, Stjernborg shows very good anticipation and awareness as soon as the puck is on the opposition’s stick. He gets on his horse and hounds the puck carrier through the neutral zone. With constant pestering, he often takes the puck away and finds open ice. There is a lot to like in Stjernborg’s game from a sense but there will be the desire to add a bit more of a dynamic element to his offensive game. His solid two-way play should be enough for a team to be intrigued though. He could play on anywhere from the second to fourth line depending on how his offensive game develops.