[1] Prior to his career at Denver, Borgström played in his native Finland within the junior program of the HIFK organization.

[8] Unable to come to terms with the Panthers as a restricted free agent and with the 2020–21 season, set to be delayed through the COVID-19 pandemic, Borgström opted to return to his original Finnish club, signing a one-year contract with HIFK of the Liiga, on 4 October 2020.

On 11 July 2022, Borgström was placed on unconditional waivers by the Blackhawks for the purpose of buying out the remaining year on his contract, he was released as a free agent the following day.

He was recalled and featured in one game with the Capitals before returning to the Bears and helping the club claim the Calder Cup, assisting on the championship winning overtime goal.

As a pending restricted free agent, Borgström opted to return to Europe in securing a two-year contract with Swedish club, HV71 of the SHL, on June 26, 2023.