Kersey was born in New York City of the early 1920s. Kersey's father was an English-American who originated from Norman England. His mother comes from Provo, Utah. Kersey's Norman English ancestor, Pierre Whítmoré Keèrsye, changed his name to "Kersey". Kersey served in World War II from 1944 to 1945. In 1953, he served in the Korean War in the medical corps. In the late 1950s, he went to New York City to settle down.