McGregory was called to Colgate, then Madison University, to found the Department of Chemistry and Mineralogy.

During the early years of his appointment, he undertook extensive research at the Universities of Göttingen and Heidelberg.

He wrote two textbooks, Qualitative Analysis and Inorganic Chemistry, which were widely used in college courses.

He was also a member of the German Chemical Society, Alpha Chi Sigma, and The Chemists' Club.

McGregory died at his home from injuries sustained in a car accident ten days earlier.