Bessler attended Mankato Loyola High School and received his B.A. from the University of Minnesota, J.D. from Indiana University School of Law, M.F.A. from Hamline University and his M.St. from Oxford University.
Bessler previously taught at the University of Minnesota Law School, where he specialized in death penalty issues and is considered a "leading authority", having written three books on the subject. Two of those books, Death in the Dark: Midnight Executions in America and Legacy of Violence: Lynch Mobs and Executions in Minnesota were Minnesota Book Award finalists. He also authored Writing for Life.
In addition, Bessler clerked for U.S. Magistrate Judge John M. Mason of the District of Minnesota, practiced law as a partner at Kelly & Berens, P.A., studied international human rights law at Oxford University and wrote articles for the Indiana Law Journal and the Arkansas Law Review.
- "George Washington University Law School Faculty Profile". George Washington University Law School. Retrieved 2008-10-31.
- Gale Reference Team (December 16, 2007). Biography - Bessler, John D. Thomson Gale.