Edfelt was the son of lieutenant August Edfelt and Ellen Hellner. He grew up in Skara, where he studied Latin and Greek at the senior high school. In fall 1923, he studied Nordic Languages at Lund University. He also attended public lectures in Philosophy and History of Literature. From 1924 to 1930, with exception from his military service in 1925–26, Edfelt studied Nordic Languages, English, German, History of Literature and Pedagogics, including a course in History of Philosophy, at Uppsala university. During this period, he attended student circles that discussed Sigmund Freud and Carl Gustav Jung.
Early career
After he had taken his master's degree in Uppsala in spring 1930, Edfelt moved to Stockholm. The financial crisis following the Wall Street crash of 1929 soon made its impact on the Swedish labor market, and in the beginning of the 30s Edfelt earned his living by writing literary reviews. In autumn 1931, he was hired as a temporary-staff master at the municipal school in Storvik in Gästrikland. During winter 1930–31, Edfelt in Stockholm became acquainted with the female artistHélène Apéria, to whom he later would dedicate his collection Aftonunderhållnng. On 2 March 1932 the couple married at Nyloftet in Skansen in Stockholm. In 1933 Edfelt temporary moved to the small town of Mariefred, where he completed his collection Högmässa under observation from the older poet Bertil Malmberg, who had settled down in the country idyll after his years in Munich.
Edfelt's mature poetry might be described as traditionalistic in form but modernistic in imagery. He got his major breakthrough in 1934 with Högmassa, which was reviewed in many Swedish dailies. By that time, Edfelt was influenced by Swedish poets such as Bertil Malmberg, Birger Sjöberg, Bo Bergman and Erik Axel Karlfeldt but also by international celebrities such as Charles Baudelaire, Bertolt Brecht and T. S. Eliot. Another characteristic trait for Edfelt's poetry from the 1930s are innumerous allusions to literature ranging from the Bible and ancient tragic playwrights to psychoanalysis and Modernism. Sometimes Edfelt even re-uses a part of the metric structure from older Swedish poets in order to create a certain mood. Aftonunderhållning 1932, I Denna Natt 1936, Vintern Är Lång 1939 and Sång för Reskamrater 1941 all belong to the same creative period as Högmässa. The contrast between dark human suffering and the redeeming flame of love distinguishes these books.
In the collections Elden och Klyftan 1943 and Bråddjupt Eko 1947, Edfelt's poetry becomes more introspective. From Hemliga slagfält 1952 onwards, there is an element of prose poetry in his collections.