He previously played for the Boston Bruins organization of the National Hockey League (NHL).

Steen made his Swedish Hockey League debut with Färjestad BK during the 2015–16 SHL season.

[3] On 24 October 2021, Steen registered his first NHL point with an assist on a Jake DeBrusk goal in a 4–3 victory versus the San Jose Sharks.

[4] On 13 July 2024, Steen returned to Sweden following five seasons within the Bruins organization, signing a five-year contract with Färjestad of the SHL.

He made his IIHF World U20 Championship debut in 2018 winning the silver medal after losing to Canada in the final.