Known best for his paintings, Chapin was born in West Orange, New Jersey and studied both at Cooper Union and the Art Students League in New York City, and later at the Royal Academy of Antwerp, Belgium. In 1924 he moved from New York to the Marvin family farm in New Jersey and there he created a series of paintings that were realistic depictions of the rigors and rhythms of rural farm life. The early paintings in the series were first exhibited in 1926 at the New Gallery in New York City in 1926, and their idiosyncratic, original style won high praise from critics and fellow artists, including Thomas Hart Benton, John Steuart Curry, and Grant Wood, whose Regionalist works were heavily influenced by them.

In 1935 Chapin accepted a position at the Pennsylvania Academy of the Fine Arts and in the late 1930s, he accepted a teaching position in California, all the while accepting commissions as a free-lance illustrator, including cover designs for major national periodicals. As a result of his opposition to United States foreign policy in Southeast Asia, Chapin moved to Canada, where he died.