Philip (Phil) Long Henderson was born on April 6, 1911 in Youngstown, Ohio to Dwight and Edith (Edie) Henderson. Henderson received his Bachelor's and Master's degrees in Fine Arts from the Chicago Art Institute in 1938 and 1941, respectively. He taught art at Cornell College in Iowa and the Escuela Universitaria de Bellas Artes in San Miguel, Mexico. Henderson also worked as a commercial artist in Detroit, Michigan.

Henderson came to the University of Kansas in 1953. In 1956 he became an assistant professor and finally associate professor in 1963, teaching courses in fashion illustration, advertising, and editorial art and design. He retired in 1980.

Henderson's concentrations of study were photography, painting in watercolor and oils, as well as sketching in charcoal, pencil, and ink. Henderson's subject matter included landscapes, nudes, and portraits. One painting, "The Blackhawks Attacking the Goal," was invited to be shown at the 1936 Olympic Games in Berlin, Germany.

Henderson married Lois Taylor in 1936 and they divorced in 1953. He married Kathryn (Kate) Arnold in 1963 and adopted her daughter, Stephanie. He divorced her in 1965. He married Virginia Benson and they divorced some time later. He was a president and trustee of the Kansas Federation of Art and was a member of the College Art Association of America. Henderson died in Lawrence, Kansas on July 12, 1998.