Born in Espoo and raised in Kaitaa neigbourhood,[3] Möller started playing football in Espoon Palloseura (EPS), before joining HJK youth academy at the age of 12. He signed his first professional contract with the club on 28 January 2022, on a three-year deal.[4] Since 2021 Möller has been playing with the club's reserve team Klubi 04 in the second-tier Ykkönen and the third-tier Kakkonen. He made his debut with HJK first team in the early 2023, in the Finnish League Cup tournament, scoring two goals in three matches.
Möller made his debut in the European competitions with HJK first team on 19 July 2023, after being substituted in the 2nd leg of the first qualifying round of the 2023-24 UEFA Champions League against Larne FC.[8] Möller also represented HJK youth in the 2023-24 UEFA Youth League, scoring one goal in four matches in total, against Malmö FF and Nantes.[9]
On 26 April 2024, while he was still recovering after a surgery, his contract was extended until the end of 2026 with a one-year option.[10] On 24 October, in a UECL league phase match against Dinamo Minsk, Möller scored the winning goal in a 1–0 home victory.[11]