Born in Philadelphia, Pennsylvania, Gammon was a teacher, painter and printmaker. Although he occasionally painted still life’s and landscapes, the human figure was his essential means of expression. Born during the Depression, he would use the figure to express his intense interest in the human condition. Gammon studied art at the Philadelphia Museum College of Art on a scholarship in 1941 and after moving to New York City in 1948 began experimenting with cubism, something that found its way into his work occasionally over the next 50 years. Years later he joined Spiral; a group of African American artists created to stimulate an exchange of evolving ideas and included several significant African American artists. He was also a member of the Black Emergency Cultural Coalition, which he formed in 1969 with Benny Andrews. After retirement, Gammon became a founding member of New Grounds Print Workshop & Gallery in 1996. It was there that he renewed his love for printmaking and developed his last body of work, a collection of over 100 prints of historically important jazz musicians and gospel singers.