Eidem was son of Anders Magnus Andersson, a merchant in Gothenburg, and his spouse Pauline Eidem, whose maiden name he took. He received his filosofie kandidat degree from the University College of Gothenburg in 1903, his theology degree from Lund University in 1907, became licentiate there in 1912 and completed his doctorate of theology in 1918. He was docent of New Testamentexegesis in Lund 1913-1924, and was assistant at Uppsala University 1918-1919. He was vicar of Gårdstånga parish 1924-1928 and professor of Biblical studies in Uppsala 1926-1928, and in Lund from 1928 until 1931, when he was elected archbishop of Uppsala. He married Elisabeth Eklund, a daughter of the theologian Pehr Eklund, dean of the cathedral of Lund and professor of church history at the university.
During the 1930s, Eidem expressed nationalist views, but kept a clear distance from the German Nazi regime and warned the Lutheran church in Germany for the prevalent antisemitism. After the war years, Eidem was one of the churchmen who donated money to the high church St. Ansgar Foundation in Uppsala.
Following the murder of Kaj Munk on 4 January 1944 the Danish resistance newspaper De frie Danske brought condemning reactions from influential Scandinavians, including Eidem.[2]
^"KAJ MUNK IN MEMORIAM". De frie Danske (in Danish). January 1944. p. 6. Retrieved 18 November 2014. Med oprørt Sind og Smerte har vi modtaget Budskabet om den uhyggelige Blodsdaad ved Silkeborg. Kaj Munk var indenfor vide Kredse i vort Land beundret som en benaadet Forkynder og en skabende Kunstner
Vem är det 1955
Sveriges dödbok 1950-1999 (CD-ROM, published 2000 by the Swedish Federation of Genealogical Societies)
