Erik Karlsson is Swedish by nationality. Erik Karlsson is a two-time winner of the James Norris Memorial Trophy as the NHL’s best defenceman, winning the award in 2012 and 2015.
Erik Karlsson made his Elitserien debut for Frölunda HC on 1 March 2008 during a sold-out home game in Scandinavium against league leaders HV71.
Erik Karlsson was selected to participate in the 2011 NHL All-Star Game on 30 January 2011, at the RBC Center in Raleigh, North Carolina, where he recorded 25 points in 41 games.
On 1 November 2022, Erik Karlsson scored his first NHL career hat trick in a 6–5 shootout loss to the Anaheim Ducks.
Erik Karlsson was selected as the tournament’s best defenceman at the 2008 IIHF World U18 Championships and was the tournament’s plus/minus leader with a plus-eight rating.
In the 2008 U20 4-Nations tournament, Erik Karlsson scored one goal and one assist which tied him with David Rundblad, Viktor Ekbom and Tim Erixon as Sweden’s defenceman-scoring leader.