Howard E. Zimmerman was a native of Connecticut. During World War II, he served in the U.S. Armored Corps in Europe where he was a tank gunner. His final rank was technical sergeant. He obtained a B. S. in Chemistry in 1950 and a Ph.D. in 1953 both from Yale University. He was a Postdoctoral Research Fellow with a National Research Council fellowship from 1953 to 1954 working with R. B. Woodward (Harvard). From 1954 to 1960 he was assistant professor at Northwestern University. Beginning in 1960 he was Associate Professor and then Professor at the University of Wisconsin, and from 1990 he was Hilldale and A. C. Cope Professor of Chemistry. His publications number over 285 (including 11 chapters).
Zimmerman gave ACS Short Courses on organic quantum chemistry and molecular orbital theory. He authored a 1975 textbook entitled Quantum Mechanics for Organic Chemists. Zimmerman was the organizer of the 1972 IUPAC Photochemistry Symposium (Baden-Baden) and of five Pacifichem Symposia – the last being Pacifichem 2010.