In 1959, Warner was one of the six founders of Johnson Corp., a manufacturer of residential heating and cooling equipment. In 1968, he founded Alsport, a manufacturer of recreational vehicles, snowmobiles, motorbikes and bicycles.
In 1976, Warner founded Industrial Powder Coatings Inc., a custom powder coater operation in Norwalk, OH, starting with seven people and one powder coating line. He developed the first engine block line and the first full-production blank-coating line.