Clifton attended Gilman School in Baltimore and Woodberry Forest School in Virginia. He made the newspapers at an early age: in August 1922, “Sunnyboy,” as the seven-year-old Clifton was then known, was put in charge of two three-year-olds, Jimmy Aldrich and Caroline Tarbell Tupper. Jimmy, the nephew of Ida M. Tarbell, and the others were staying at Tarbell’s country house near the Housatonic. While throwing rocks into the river from a bridge, Jimmy lost his balance and fell in, striking his head and becoming trapped among sticks and weeds. Clifton dove in, pulled him out, and administered artificial respiration. He had learned to swim at Fire Island, where his parents maintained a summer house.

Before World War II Clifton worked in banking and advertising in Washington, D.C. During the war he served as a lieutenant colonel in antiaircraft artillery, seeing action in Africa, Sicily, Italy, France, and Germany. After the war he joined the Louis Marx Company, a toy manufacturer, and later worked for IBM.

He died in 1952 following a lung operation at Walter Reed Hospital.