He was assigned to the Manitoba Moose in his first season with the Canucks organization and was named to the American Hockey League's 2010–11 All-Rookie Team.

[2] In October of 2024 Lack became a dual American citizen Läck spent his minor hockey career with his hometown team, Norrtälje IK.

[4] Läck made his professional debut with Leksands IF's men's team in the HockeyAllsvenskan, Sweden's second-highest league, appearing in three games in 2006–07.

[5] After three seasons with the Leksands IF organization, Läck moved up to the Elitserien, Sweden's premiere league, signing a two-year contract with Brynäs IF on 6 July 2009.

[3] He made his Elitserien debut on 17 October, relieving Jacob Markström (who at the time was a Florida Panthers prospect) near the end of the first period.

Following the Manitoba's elimination to the Hamilton Bulldogs,[10] Läck was called up to the Canucks on 13 May 2011,[6] to travel and practice with the team as a playoff reserve.

Positioned behind Roberto Luongo and Cory Schneider (joint winners of the 2010–11 William M. Jennings Trophy) on the Canucks' depth chart, Läck was assigned to the AHL for a second season in 2011–12.

Due to the Winnipeg Jets' return to the NHL, the Moose franchise was relocated to St. John's, Newfoundland; as a result, the Canucks switched their AHL affiliation to the Chicago Wolves.

By season's end, he, along with backup Matt Climie, helped set a Wolves franchise record for lowest team goals against average at 2.54.

[17] On 15 November, despite Läck having only made five NHL appearances to date, the Canucks re-signed him to a two-year contract extension worth a total of U.S.$2.3 million.

[30] Originally slated in the backup role to Viktor Fasth, Läck made his international debut in the round-robin stage, posting a 19-save shutout in a 2–0 victory over Latvia on 11 May 2017.

[31] With the addition of starting goaltender Henrik Lundqvist to the roster mid-tournament, Läck was subsequently demoted as Sweden's third-choice.

On 14 August 2019, Läck announced that he would be taking a break from playing ice hockey to focus on rehabbing his hip injury, and accepted a position as goaltender coach for Arizona State University.