Davis was born in 1913 at Dunedin, New Zealand. He received his education at Otago Boys' High School and the University of Otago, where he was taught by Professor Herbert Ramsay. He was awarded a Rhodes scholarship to Merton College, Oxford, in 1934 and studied comparative philology. From 1937–38, he lectured in English at the University of Kaunas in Lithuania, and then at the University of Sofia, Bulgaria, 1938–39.
According to his biographer James McNeish, Davis was "undistinguished in appearance" and had a talent for mimicry. When the Second World War broke out, he was recruited by the Special Operations Executive of British Intelligence and became Assistant Press Attache at the British Legation in Sofia. In 1941, he warned the British ambassador in Sofia George William Rendel of the imminent Bulgarian entering of the Axis. He smuggled the leader of the Bulgarian resistance G. M. Dimitrov out of Bulgaria to the safety of the British Legation in Turkey (January-February 1941). He was trying to escape from Yugoslavia when he was captured by the Italians and interned in Italy for three months, before being repatriated to England. He continued his clandestine work, operating out of Turkey under an assumed name. His wife Lena was also "in the firm".
Davis and G. M. Dimitrov were tried in Sofia for subversion and sentenced in absentia to execution by hanging. At the end of the War, Davis had reached the rank of major and in 1945 was awarded the MBE.
He resumed his university teaching, as a lecturer in English language at Queen Mary College, University of London, in 1946, having proceeded to MA at Oxford in 1944. He was then appointed to a similar position at Oriel and Brasenose Colleges, Oxford, where he also lectured in Medieval English. From 1949 to 1959, he taught at Glasgow University. He then followed J. R. R. Tolkien as Merton Professor of English Language and Literature at Oxford, until his retirement in 1980.
According to McNeish,"... he liked to say that his achievement was that he "added a letter to the Bulgarian alphabet", but his monument is the great edition of the Paston Letters, "a text throwing light on the attitudes of a 15th-century English family in Norfolk on the make."
Davis died in Oxford on 2 December 1989. Practically his entire estate was left to the University of Otago. According to McNeish, the proper use of the funds was contested by the executor, as the University Council decided to use them to fund visiting academics, rather than sending New Zealand scholars to benefit from study at Oxford.
- McLintock, A. H., ed. (22 April 2009) [First published in 1966]. "United Kingdom". An Encyclopaedia of New Zealand. Ministry for Culture and Heritage / Te Manatū Taonga. Retrieved 31 July 2015.
- McNeish 2003, p. ?.
- McNeish 2003, p. 368.
- McNeish 2003, p. 370.
- Davis, Norman in Who's Who online edition (subscription required), accessed 26 May 2011
- McNeish 2003, p. 369.
- "NormanDavis 1913–1989" (PDF). University of Otago. Retrieved 11 January 2016.
- McNeish 2003, p. 372.
- McNeish, James (2003). Dance of the Peacocks: New Zealanders in exile in the time of Hitler and Mao Tse-Tung. Virago.