Jon James Tollefson was born on April 20, 1945, in Minneapolis, Minnesota. He earned a B.A. (1967) in biology from Gustavus Adolphus College in St. Peter, Minnesota and Ph.D. (1975) in entomology at Iowa State University.



Tollefson was a Research Assistant (1967-1969) for the Department of Entomology at the University of Nebraska, before serving as a small-unit combat leader (1969-1971) in the United States Army. He began his career at Iowa State University as entomology Research Assistant (1971-1972), later became a Pre-doctoral Research Associate (1972-1975). After receiving his degree, Tollefson became an Assistant Professor (1975-1979) in the Department of Entomology at Iowa State and was promoted to Associate Professor (1979-1988). He then became Professor (1988-present) and he also served as Department Chair (2004-2007) for the Department of Entomology.



At Iowa State University, Tollefson has served on the Faculty Senate (1987-1995) and the Graduate Council (1995-1996). He has been a member of several professional associations and honor societies including the Entomological Society of America, the Kansas Entomological Society, Phi Kappa Phi, Sigma Xi, and Gamma Sigma Delta.



Tollefson's research focused on crop pests, specifically corn rootworms. He directed the Corn-Insect Research Project, which investigated new chemical and biological tools for use in rootworm integrated pest management. He researched ways of using sampling techniques to monitor pest populations and studied the biodegradation of insecticides in the fields.

Jon Tollefson married Carla (Rudquist) and they had two daughters, Kirsten and Karin.