In 1916, at age 16, Björk was promoted to the senior squad of Hammarby IF.[2][3][4] Björk soon became known as a prolific goalscorer and established himself as one of Hammarby's key players, together with goalkeeper Victor Olsson and defender Gösta Wihlborg.[5][4][6]
In 1920, Hammarby debuted in the Svenska Serien, by then the highest league in Swedish football. The club finished third in the table, three points behind winners Örgryte.[7] The same year, Björk won two caps for the Sweden national football team, featuring in two 0–3 losses against Norway and Finland[8][6]
In 1922, Hammarby had an other strong showing where they went to the finals of Svenska Mästerskapet, a cup by then held to decide the Swedish champion, losing 1–3 to GAIS in a game where Björk scored the consolidation goal.[9][4]
In 1924, Hammarby IF was one of the founding members of Allsvenskan, a new league that was established to determine the Swedish champion.[10] He was forced to retire from football in 1925 due to suffering from diabetes.[11]
Like many footballers at the time, Björk also played bandy with Hammarby IF between 1918 and 1925.[12][10][6]
In 1921, the club founded their ice hockey department, and on 7 March the same year, Björk became the very first goalscorer for Hammarby IF in a 7–5 win against IF Linnéa.[7] He was part of their roster for two seasons in total.[13]
