2010-11: Carl Dahlstrom made his debut in the Swedish U18 Allsvenskan, playing one game for Djurgarden, and was with the club's U16 team as well as skating for Stockholm 1 in the TV-Pucken tournament for high school players. He was scoreless in his only U18 game. In six games with the Djurgarden U16 team he scored 2 goals with 1 assist and had 25 penalty minutes. Stockholm 1 won the gold medal in the TV-Pucken tournament and Dahlstrom finished with 1 goal and 1 assist in eight games.
2011-12: Dahlstrom played for the Djurgarden U18 team. He scored 2 goals with 13 assists in 37 regular season games and was +31 with 4 penalty minutes. Djurgarden reached the second round in the U18 playoffs and in four games Dahlstrom was +5 with 3 assists.
2012-13: Dahlstrom skated for the Linkoping U20 team as a 17-year–old, appearing in 37 regular season games and five playoff contests. He was +18 with 5 goals and 8 assists during the regular season and was -1 with 1 goal and 1 assist and 4 penalty minutes in five playoff games .He skated in nine international games for Sweden's U18 team but was not with the fourth place squad at the 2013 U18 World Championship. Dahlstrom was ranked 18th amongst European skaters in Central Scouting's final rankings and was selected by Chicago in the second round (51st overall) of the 2013 NHL Draft.
Dahlstrom is a rangy, stay-at-home defenseman. He is mobile and has a big frame at 6'3, even though he still needs to work on filling it out. The Swedish blueliner is still capable of using his body to move players around, but is generally a player that will maintain his defensive posture rather than chase a big hit. Not a player to push the envelope much offensively, Dahlstrom is nonetheless capable of making a good breakout pass and getting the puck on net. He plays a smart, safe game with the puck on his stick, but may not be a player that generates a ton of offense as he transitions to the pro level.
Dahlstrom is expected to return to the Linkoping J20 club in Sweden in 2013-14, but he may have a chance to skate in the Swedish Hockey League at some point. He will also be in the mix on the blue line for Sweden's WJC team.