Stempel was a member of the National Academy of Engineering, the Society of Automotive Engineers, the American Society of Mechanical Engineers, and the Engineering Society of Detroit. He was the first chairman of the American Quality Foundation, developed by the American Society for Quality Control. He was a member of the board of directors and chairman of the National Industrial Advisory Council to the Opportunities Industrialization Centers of America, Inc.; the National Minority Supplier Development Council; and the Motor Vehicle Manufacturers Association; the Highway Users Federation and the United Way of Southeastern Michigan. He was a member of Detroit's Conference Board, The Business Roundtable, and The Business Council and he was a trustee of Worcester Polytechnic Institute, Detroit Renaissance, and New Detroit, Inc.