Opting to continue his development in North America, Lagesson was selected 11th overall in the 2014 United States Hockey League (USHL) Entry Draft by the Dubuque Fighting Saints.

[1] He played in the 2014–15 season with the Fighting Saints of the USHL, before committing to a collegiate career with the University of Massachusetts Amherst of Hockey East.

Lagesson played two years with the struggling Minutemen program before leaving after his sophomore season and deciding to turn pro, in signing a three-year entry-level contract with the Edmonton Oilers on 7 April 2017.

Returning to the Oilers over the summer, and after participating in the NHL training camp, Lagesson was assigned to begin the 2018–19 season with their American Hockey League (AHL) affiliate, the Bakersfield Condors, on 20 September 2018.

[8] On 1 July 2023, Lagesson left the Hurricanes organization and signed as a free agent to a one-year, two-way contract with the Toronto Maple Leafs.

Approaching the NHL trade deadline, Lagesson was placed on waivers by the Maple Leafs, and was subsequently claimed by the Anaheim Ducks on 9 March 2024.

[20] He returned for Sweden at the 2016 World Junior Ice Hockey Championships, playing on the top pair alongside Gustav Forsling, winning their group.