Karlsson played two season with the
Green Bay Gamblers of the
United States Hockey League (2009–2011), scoring a total of 70 points (24 goals). Before appearing in a game with the Solar Bears in the
2015–16 season, Karlsson was traded for future considerations to the
Colorado Eagles on 26 October 2015. At the conclusion of his entry-level contract, and failing to establish himself in the professional ranks, Karlson was not tendered a qualifying offer to remain with the Stars. As a free agent, Karlsson opted to return to his native Sweden, signing a one-year deal with second division club,
IK Pantern of the
HockeyAllsvenskan on 28 April 2016. After a spell in Sweden, Karlsson moved to the UK in the summer of 2017 to sign for
MK Lightning ahead of their inaugural
EIHL season. Karlsson suffered an unusual amount of injuries throughout his professional career. In 2018 Karlsson suffered a season-ending compound fracture in his wrist, after which he retired. ==References==