After establishing his own firm in 1972, Stumpf created the Ergon chair, the first ergonomic work chair. Later, in collaboration with Don Chadwick, he produced the groundbreaking Equa and iconic Aeron chairs. He also was principal designer for the Ethospace system.

Stumpf is a graduate of the University of Wisconsin and also taught at the university's Environmental Design Centre.

During his lifetime, Stumpf was a key figure in Herman Miller's transformation into a research-based, problem-solving innovator received numerous awards for this work. He was named the winner of the 2006 National Design Award in Product Design, an award presented by the Smithsonian's Cooper-Hewitt, National Design Museum.