Working as a professor at the University of Oslo from 1947 to 1981, he did groundbreaking research in Uralic (especially Sami) and Eskaleut languages.
He was born in Kristiania as a son of engineer Einar Christian Bergsland (1883–1945) and Henriette Louise Krogh Raabe (1883–1958).
His first linguistic work was a grammar of the Southern Sámi language, released as Røros-lappisk grammatikk in 1946.
In 1947 Bergsland was appointed professor in Finno-Ugric languages at the University of Oslo, succeeding Konrad Nielsen.
He continued his work on Sami languages, and also did important research in Eskaleut languages, firstly a historical grammar of Kalaallisut (or Western Greenlandic), and then a dictionary and reference grammar of Aleut.