[3] He returned to the IBU Cup on 14 January 2021, and was placed 2nd in his first competition as a senior - The Men's 10 km Spring in Arber.

[5] By winning the total score, he earned a spot in the 2020-21 Biathlon World Cup final in Ostersund, where he finished 58th in the Sprint and 35th in the Pursuit.

In the 2021-22 Biathlon World Cup, he competed as part of the Norwegian A-team in the season opening in Ostersund, where he was ranked 9th in the 10 km sprint competition.

He continued as part of the A-team for the rest of the season, winning gold in the Men's relay and bronze in the sprint in Kontiolahti.

[7] On 31 March 2022, it was announced that Andersen would be competing as part of the Elite Norwegian team in the 2022-23 season.