McDunnough travelled with his mother and aunt to Berlin to be trained as a classical musician, studying under the great violinist Joseph Joachim.
[1] Returning to North America, he worked briefly at the Marine Biological Laboratory in Woods Hole, Massachusetts and married Margaret Bertels, from Berlin.
He soon learned of an important opportunity: a wealthy surgeon in Decatur, Illinois named William Barnes needed an entomologist to serve as curator and researcher for his private collection of North American Lepidoptera - probably the best in existence at the time.
[3] During those 28 years, he oversaw the development of the Canadian National Collection into a world-class repository of insect and other arthropod specimens along with an extensive library of entomological publications, conducted faunal surveys throughout Canada, and published 199 taxonomic papers.
After retirement, he was appointed a research associate at the American Museum of Natural History, working there from late 1946 to 1950.