After graduating in 1965 from Yale University, Kohler went to work for the Kohler Company which long has been a manufacturer of bathtubs, toilets, other plumbing fixtures, and small engines. He worked as a laborer or technician in every division of the company. In June 1972, he was elected chairman of the board and chief executive officer at the age of 33. Under his leadership, the company more than doubled the size of its engine and generator business and it launched an interiors group that now encompasses five furnishings lines.