Flom 1920 to 1940. DeFeo was very active as an illustrator. Sporting and adventure stories were his most important subjects. DeFeo himself was an avid sportsman and an authority on fishing. The artist also illustrated books, including several by Roderick Haig Brown, with whom Defeo travelled extensively. Yet, adventure sports were net DeFeo's ony subject; he often illustrated the life of the flapper in Liberty, McCall's, and Cosmopolitan.
After 1940, DeFeo devoted his time to easel painting, predominately of wildlife.DeFeo's style shows a debt to Harvey Dunn, with whom he is reported to have studied. Like Door, DeFeo relied on bold coloration to express the impact of the scene being illustrated.DeFeo was active in many artist associations in New York, including the American Water Color Society, the National Academy of Design, and the Salmagundi Club. He died in New York in 1978.