League play started in April, initially behind closed doors due to the coronavirus pandemic.

Stefan Billborn made his fourth season as manager, but was sacked after eight rounds and replaced by Miloš Milojević.

On 30 May 2021, Hammarby IF won the 2020–21 Svenska Cupen, their first title in the main domestic cup, through a 5–4 win on penalties (0–0 after full-time) against BK Häcken in the final.

[1][2] On 11 June 2021, Hammarby decided to terminate manager Stefan Billborn's contract, with the club placed 8th in the 2021 Allsvenskan table after eight rounds.

[3] On 13 June, Miloš Milojević, most recently an assistant at Red Star Belgrade, was appointed new head coach.