Knox Martin was born in 1923 in Barranquilla, Colombia. He was the son of the aviator, painter, and poet William Knox Martin, the first man to fly over the Andes mountains.
After serving in World War II, Martin attended the Art Students League of New York on the G.I. Bill from 1946-1950, where he studied with Harry Sternberg, Vaclav Vytlacil, Will Barnet, and Morris Kantor.
Martin was a celebrated painter, sculptor and muralist. He also led a distinguished career teaching art at Yale Graduate School of the Arts, New York University, University of Minnesota, International School of Art in Umbria, Italy, and Fort Rajgad, India. For over 45 years, Martin gave a legendary Master Class at the Art Students League of New York.