Dieter Geuenich was born on 17 February 1943 in Bad Honnef, Germany.

From 1972 to 1982, Geuenich was a research assistant in history at the University of Freiburg.

He was appointed Chair of Medieval History at the University of Duisburg-Essen in 1989.

Geuenich became a corresponding member of the Göttingen Academy of Sciences and Humanities in 2000.

He was a co-editor of the second edition of the Reallexikon der Germanischen Altertumskunde.