Haugen was born in Sioux City, Iowa to Norwegians from the town of Oppdal in Norway. When he was a young child, the family moved back to Oppdal for a few years, but then returned to the United States. He attended Morningside College in Sioux City but transferred to St. Olaf College to study with Ole Edvart Rølvaag. He earned his B.A. in 1928 and immediately went on to graduate studies in linguistics at the University of Illinois at Urbana-Champaign, where he was awarded his Ph.D. in 1931.
In 1931 Haugen joined the faculty of the University of Wisconsin–Madison, where he stayed until 1962. He was made Victor S. Thomas Professor of Scandinavian and Linguistics at Harvard University in 1964, and stayed here until his retirement in 1975. Haugen served as president of the Linguistic Society of America, the American Dialect Society, and the Society for the Advancement of Scandinavian Study. Haugen was also a member of the Board of Editors of the Norwegian-American Historical Association. 
Haugen is credited for having pioneered the field of sociolinguistics and being a leading scholar within the field of Norwegian-American studies, including Old Norse studies. Perhaps his most important work was The Norwegian language in America; A study in bilingual behavior (ISBN 0-253-34115-9). In addition to several important works within these fields, he wrote the authoritative work on the dialect of his ancestral home of Oppdal and a book entitled The Ecology of Language, with which he pioneered a new field of linguistics later called Ecolinguistics. Einar Haugen also wrote Norwegian American Dictionary/Norsk engelsk ordbok (ISBN 0-299-03874-2).
The Einar and Eva Lund Haugen Memorial Scholarship has been established by the Norwegian-American Historical Association to honor Einar Haugen and his wife Eva Lund Haugen. Additionally, the Boston Chapter of the American-Scandinavian Foundation voted to establish the Einar and Eva Haugen Prize. The prize is awarded annually to an undergraduate or graduate student for excellence in the field of Scandinavian languages and literature at Harvard University.
- Voyages To Vinland: The First American Saga (1942)
- Spoken Norwegian (1946)
- The Norwegian Language in America: A Study in Bilingual Behavior (1953)
- Bilingualism in the Americas (1956)
- Language Conflict and Language Planning: The Case of Modern Norwegian (1966)
- Studies by Einar Haugen: Presented on the occasion of his 65th birthday ( 1971)
- The Ecology of Language; Language science and national development (1972)
- Norwegian-English Dictionary: A Pronouncing and Translating Dictionary of Modern Norwegian (1974)
- The Scandinavian Languages: An Introduction to their History (1976)
- Bibliography of Scandinavian Languages and Linguistics 1900-70 (1974)
- Scandinavian Language Structures (1982)
- Immigrant Idealist: A Literary Biography of Waldemar Ager, Norwegian American (1989)
- Ole Bull: Norway's romantic musician and cosmopolitan patriot (1993)
- Schizoglossia, term coined by Haugen
- Einar Haugen (1906-1994) (Lloyd Hustvedt. Swedish-American Historical Society. April 1995, v.46, no.2, pages 141-142)
- Einar Haugen, leading authority on Norwegian culture in US (The Boston Globe. Boston, MA. June 25, 1994)
- Memorial minute from Harvard University
- Haugen, Einar; Cai, Camilla (1993), Ole Bull: Norway's romantic musician and cosmopolitan patriot, University of Wisconsin Press, ISBN 978-0-299-13250-7
- Einar and Eva Haugen Prize (The President and Fellows of Harvard College)
Lovoll, Odd S. The History of the Norwegian-American People (Minneapolis, MN: University of Minnesota Press. 1999)