Duffie is a professor emeritus of mechanical engineering and past department chair for the Department of Mechanical Engineering at UW-Madison. His research interests are in machine, process, and system control, particularly distributed system control. He received a bachelor’s degree in computer science, a master’s degree in engineering, and a PhD in mechanical engineering from UW-Madison. Duffie is a fellow of ASME, CIRP, and SME. He is a fellow of CIRP (International Academy for Production Engineering), ASME, SME, and is a past president of SME. In 2008, he was Mercator Guest Professor at the University of Bremen, Germany.