Neumann studied scholastic theology and philosophy from 1922 to 1934 in Innsbruck and Oxon, England, before going on to study German and English languages and literature, Nordic languages, history, and philosophy in Marburg from 1935 to 1939. From 1951 to 1955, he taught German language and literature in Göttingen.
In April 1955, Neumann accepted an invitation to Freie Universität Berlin as a visiting professor. In 1959, he was made a full professor of German language and literature, Old and Middle German languages and literatures, and Nordic languages and literatures. He taught at Freie Universität until his retirement, in 1971.