Fretwell was president of Buffalo State College in New York from 1967 to 1978.
He oversaw the creation of the Graduate School, created more graduate degrees, integrated the library's card catalog onto an Intranet in 1983, created the ground work for a major business incubator, helped to develop the university's surrounding neighborhood, and increased academic grants to over $6.1 million.
The building headquarters the College of Humanities & Earth and Social Sciences.
Fretwell served as interim president of the University of Massachusetts from 1991-1992.
In 1998, Fretwell served as the interim president of the University of North Florida.