 Kassay taught industrial arts in junior and senior high schools in Kansas and, for over thirty years, at San Francisco State University, where he was professor in the Department of Design and Industry.Kassay taught courses in woodworking technology and construction at San Francisco State, running "probably the finest woodworking program in America" according to Tom McFadden in Cabinet Maker magazine.In 1980, Kassay published "The Book of Shaker Furniture" to wide acclaim.