Career
Træen joined UCI Continental team Team Ringeriks–Kraft in 2015. He competed in the men's team time trial event at the 2017 UCI Road World Championships.
In 2022, Træen placed ninth overall at the Volta a Catalunya followed by a strong performance at the Tour of the Alps, winning the mountains classification and placing fifth on the final stage. However, soon after the race, he was found to have testicular cancer, detected in a doping control test which revealed the presence of hCG in his blood. He was able to return to competition in August and soon returned to form, obtaining a seventh place overall at the CRO Race and third place at the Tour de Langkawi.
In 2023, he competed in his first Tour de France following an 8th place finish at the Critérium du Dauphiné. However, he crashed on stage one and broke his elbow, but elected to continue the race and ultimately finished in 95th overall.
After nine seasons with the Uno-X Pro Cycling Team, he joined UCI WorldTeam Team Bahrain Victorious for the 2024 season. In June, he took his first pro win on stage four of the Tour de Suisse in a solo victory.
Træen took part in the 2025 Vuelta a España. He took the red jersey on Stage 6 of the race after joining the day's breakaway, finishing in second place on the stage behind Jay Vine. He lost the jersey to Jonas Vingegaard on Stage 10, and finished the race in ninth place in the General Classification.
Traeen rejoined UCI WorldTeam Uno-X Pro Cycling Team signing for the 2026 and 2027 seasons. In the 2026 Tour de France Traeen finished stage 4 in 8th place and went into the overall lead and wore the yellow jersey in stages 5 and 6. During stage 6, while in the yellow jersey, he crashed into his own teammate on a hairpin turn, and had to abandon the Tour at the end of that stage.
