Pedersen got his debut for Tromsø when he came in as an 86th-minute substitute in a Norwegian Cup first round tie against Skjervøy on 18 April 2018.[4] He got his league debut in a 1–0 loss against Odd on 28 October 2018, and became the first player from Hammerfest to play in the top division of Norwegian football.[5]
On 5 May 2019, he received a red card for a professional foul and was sent off in the 88th minute of the game against Kristiansund.[6]
Molde
On 11 February 2020, Pedersen signed a three-year contract with Molde.[7]
Feyenoord
On 22 June 2021, Molde confirmed that they had sold Pedersen to Feyenoord,[8] with the Dutch club confirming the arrival of the defender on a five-year contract the same day.[9] He scored his first goal for the club on 18 February 2023, scoring the second goal in the 90th minute in a 2–1 win over AZ Alkmaar.[10]
Sassuolo (loan)
On 22 August 2023, Pedersen joined Italian club Sassuolo on loan for the remainder of the season, with an option to buy.[11]
Torino (loan)
On 22 August 2024, Pedersen returned to Italy and signed with Torino on loan, with an option to buy and a conditional obligation to buy.[12]
International career
Marcus Holmgren Pedersen played nine games and scored one goal for Norway under-19.[13] On 27 February 2019, he scored in his debut game against Denmark which Norway lost 2–1. Pedersen was a member of Norway's squad in the 2019 European Under-19 Championship[14] and appeared in all three matches in the group stage.