Having previously played a forward position in ice hockey, Dahlberg is considered one of the greatest European referees for his ability to read the game.

[4] He played for Surahammars IF in the then-highest Swedish league Hockeyettan before making his Sweden national ice hockey team debut in 1954.

As a result, his name was suggested as a suitable candidate to referee the Canada and Soviet Union Summit Series in 1972.

[9] As a compromise, Josef Kompalla and Batja officiated the match, which ended with Canada winning the title.

[9] Later in his career, he judged further contentious matches such as the United States and Soviet Union exhibition games prior to the 1976 Canada Cup which drew 29 penalties.