He began his career in 1975 at Bell Telephone Laboratories, where he stayed for 26 years before joining the University of Minnesota in 2001.

In the early 1970s, he was a co-author (with D. Kahaner and Gian-Carlo Rota) of one of the founding papers of the modern umbral calculus.

In mathematics, he is probably known best for his work on the Riemann zeta function, which led to the invention of improved algorithms, including the Odlyzko–Schönhage algorithm, and large-scale computations, which stimulated extensive research on connections between the zeta function and random matrix theory.

[5] In the paper "Content is Not King", published in First Monday in January 2001,[6] he argues that In 2012, he became a fellow of the International Association for Cryptologic Research[7] and in 2013 of the American Mathematical Society.

[8] Empirical tests, in part stimulated by this criticism, strongly support Metcalfe's law.