Kelly enrolled in the School of Industrial Art (now the Philadelphia College of Art) in 1921 and later studied with Arthur B. Carles and Earle Horter at the Pennsylvania Academy. Horter's interest in Cubism and his private collection of paintings and books strongly influenced Kelly's early work, which resembled analytic Cubism. During six years in Paris, however, Kelly elected to copy old masters at the Louvre rather than to seek out the city's avant-garde artists. By the early 1940s he was experimenting with Surrealism, creating macabre canvases depicting enormous insects and abstract forms resembling flayed human musculature. In his later years Kelly returned to figurative art, declaring that "we must resolve everything in the form of our own being."
Virginia M. Mecklenburg Modern American Realism: The Sara Roby Foundation Collection (Washington, D.C.: Smithsonian Institution Press for the National Museum of American Art, 1987)