[4] Although he played for the Calgary Northstars on the Bantam AA Blazers during their 2010–11 season, his playmaking ability and skill earned him a promotion to Midget AAA.
[12] Leading up to the draft, Wagner's final ranking by the NHL Central Scouting Bureau was 35th overall amongst North American skaters[13] and third in Anaerobic Fitness: Peak Power Output.
[20] During the off-season prior to the 2017–18 season, Wagner required shoulder surgery to repair a torn labrum and dislocated bicep tendon.
[21] After he was medically cleared to play, Wagner was assigned to the Kings American Hockey League (AHL) affiliate, the Ontario Reign.
[29] Prior to the trade deadline, he played alongside Nate Thompson, who he considered a mentor, before joining Trevor Lewis and Kyle Clifford as their winger.
He notched nine goals and 12 points through 24 games before he was dealt at the NHL trade deadline by the Kings to the Chicago Blackhawks in exchange for future considerations on March 3, 2023.
[35] Leaving Sweden and Oskarshamn at the conclusion of his contract, Wagner returned to North America and was named to the training camp roster of the Chicago Wolves in the AHL for the 2024–25 season.
[36] In April 2020, Wagner, Adrian Kempe, Ben Hutton, and Blake Lizotte joined FaZe in an eSports gaming event to raise money for charities affected by COVID-19.