After playing for both Heming, and Stabæk at youth level, he transferred to Vålerenga in 2017.[2]
In the summer of 2018, after already appearing several times for Vålerenga's second team, Opsahl signed his first professional contract with the club.[3] Opsahl appeared in both of Vålerenga's UEFA Conference League games in 2021, coming in as a substitution in both games.[4][5]
For the latter half of the 2019 season, Opsahl was loaned out to the 1. divisjon club Skeid.[6] He returned to Vålerenga after the season, making no appearances for the first team.[1]
Tromsø
In February 2022 Opsahl was sold from Vålerenga to fellow Eliteserien club Tromsø.[7]
For the first half of the 2024 season, Opsahl was on loan at Egersund, making six appearances in total, three in the league, and three in the cup.[8][2]