By the 1940s, Kuhn’s behavior began to take on unsound characteristics. He became increasingly irascible and distant from old friends. When the Ringling Brothers Circus was in town, he attended night after night. (During a hard-pressed period in the 1920s, Kuhn had worked as a designer and director for revues and circus acts.) He also became frustrated by the lack of attention his own work was receiving and was particularly strident about the Museum of Modern Art's support of abstraction and neglect of American art in the postwar period. In 1948, he was institutionalized, and on July 13, 1949, he died suddenly from a perforated ulcer. He is interred in Woodlawn Cemetery in The Bronx, New York City.