Isak Fahlén entered the world of esports in 2018, starting his career in the CS:GO discipline. His first team was Brbdmalite, but he was unable to achieve any notable results there. He then moved to Valorix Esport, where success also eluded him. The only highlight during this period was reaching the TOP-4 at the Svenska Elitserien 2019 Fall tournament.
At the end of 2019, Isak joined Prima eSport, and together with this team, he finally won his first career medal - silver at the Fragleague Season 3 tournament. After that, Isak won gold at BirdieLAN 30 and took bronze at Svenska Elitserien Spring 2020.
In the fall of 2020, Isak signed with Lilmix and quickly became one of the team's leaders. With his new team, he placed 1st-4th at Flashpoint Season 2: Open Qualifier #2, won gold at OMEN CS:GO Open Season 3, ESEA Cash Cup: Europe - Autumn 2020 #3, Svenska Elitserien Fall 2020, ESEA Cash Cup: Europe - Spring 2021 #4, and also finished 1st-2nd at Flashpoint Season 3: Open Qualifier #2.
In 2021, Fahlén joined GamerLegion, where he won gold at ESEA Cash Cup: Europe - Spring 2021 #5, PGL Major Antwerp 2022: European RMR - Open Qualifier #4, and Esportal Global Open 2022: Swedish Qualifier. After that, Isak continued competing with GL, but from April 2023 to May 2024, he was unable to achieve significant success. This led to changes in his career, and the esports player signed with Ninjas in Pyjamas, where he remains today. With his new team, Isak “isak” Fahlén has yet to win major tournaments, and his only success so far is silver medals at YaLLa Compass 2024 and Svenska Cupen 2024, as well as a 3rd-4th place finish at YaLLa Compass Fall 2024.
Since January 2025, the player has joined the Metizport roster.