Constant was a pioneering modernist painter and printmaker. A member of the Federation of Modern Painters and Sculptors, Constant also worked in the WPA and other Federal Art Projects and began exhibiting regularly from the late 1920s in the important annuals and invitationals held at major institutions across the country which comprised a dominant feature of the American art scene from the 1920s through 1960s. The Whitney Museum of American Art, Pennsylvania Academy of Fine Arts and Victoria and Albert Museum were some of the places which showed his work.
He was born in Greece, and after emigrating to the United States in 1910, he studied at Washington University in St. Louis, the Art Institute of Chicago, Illinois, and with Charles Hawthorne and George Bellows, probably at the Art Students League, in New York City.
From 1919 to 1921, he taught at the Dayton Art Institute, and then moved to New York City where he was based the remainder of his life.