A professor at the University of Göttingen, he was recognized as one of the world's leading experts on Germanic Antiquity.

At Vienna, Düwel was strongly influenced by philologist Otto Höfler, who introduced him to the field of Germanic studies.

Upon his return to Göttingen, Düwel studied Germanic philology under Wolfgang Lange and Hans Neumann, and medieval history under Percy Ernst Schramm and Hermann Heimpel [de].

The preparation for his habilitation was funded with a grant from the Deutsche Forschungsgemeinschaft, which enabled him to conduct research in Scandinavia.

Düwel contributed a large number of articles to the second edition of Reallexikon der Germanischen Altertumskunde.