He served in the military for two years before attending Ohio State University, where he earned his B.S.
[2] During the time between his undergraduate and graduate studies, Frey worked for the Public Health Service.
After earning his Ph.D., he worked as a postdoctoral fellow for enzymologist Frank Westheimer at Harvard University.
Frey then secured a faculty position in the chemistry department at the Ohio State University.
He held that position for several years, but in 1981 he joined the faculty at the Institute for Enzyme Research (now a part of the biochemistry department) at the University of Wisconsin-Madison.