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.[2]
On 8 May 2017, it was announced by the Oilers that Lagesson would spend the 2017–18 season in Sweden on loan with Djurgårdens IF of the Swedish Hockey League (SHL).[3] While with Djurgården, Lagesson made his professional debut in solidifying a regular role on the blueline. In 49 appearances, he contributed with 1 goal and 12 assists for 13 points in the regular season.[4] He continued his steady play in the post-season with an assist in 11 games.
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.[5] As an impending restricted free agent with the Oilers and with the commencement 2020–21 North American indefinitely delayed due to the COVID-19 pandemic in North America, Lagesson signed a one-year contract in Sweden with second-tier club, HC Vita Hästen of the HockeyAllsvenskan, on 23 September 2020.[6] He registered three goals and 12 points in 14 games with Vita Hästen.[4]
During the 2021–22 season Lagesson returned to North America and played in 30 games with the Oilers, registering four points and 11 games with the Condors, scoring two points.[7] On 21 March 2022, Lagesson was traded by the Oilers, along with a conditional second round pick in the 2022 NHL entry draft and a 2024 seventh-round pick to the Montreal Canadiens in exchange for defenceman Brett Kulak.[7] Following the conclusion of his contract with the Canadiens, Lagesson as a free agent was signed to a one-year, two-way contract with the Carolina Hurricanes on 25 July 2022.[4] However, Lagesson never played with the Hurricanes, spending the entire 2022–23 season with Carolina's AHL affiliate, the Chicago Wolves. He played in 65 games scoring 10 goals and 32 points.[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.[8] He attended the Maple Leafs 2023 training camp, but failed to make the team and was placed on waivers. After going unclaimed Lagesson was assigned to the Maple Leafs AHL affiliate, the Toronto Marlies to start the 2023–24 season.[9][10] After an injury to Jake McCabe, the Maple Leafs recalled Lagesson on 27 October.[11] He made his Maple Leafs season debut on 28 October in a 3–2 overtime loss to the Nashville Predators.[12][13] Lagesson in a third-pairing role remained with the Maple Leafs and appeared in 30 regular season games adding four assists.
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.[14] Lagesson made his Ducks debut on 12 March 2024 in a 7–2 loss to the Chicago Blackhawks.[15] He completed the season with the Ducks going scoreless through ten games.[16]
On 1 July 2024, Lagesson signed as a free agent to a one-year, $775,000 contract with the Detroit Red Wings.[16] He was placed on waivers and after going unclaimed, was assigned to Detroit's AHL affiliate, the Grand Rapid Griffins, for the 2024–25 season.[17][18]