Kennedy was born on February 18, 1925 in New York City. He studied at Chaminade High School and at Tarleton State University. He married Dorothy Gillooly in the 1940s. He was married to Norma Wurman from 1959 until they divorced in 1971. He remarried Wurman in 1973; they divorced again in 1978. He was married to Joan McCarthy from 1978 until her death in 2015. He had two children. He lived in Eagle, Idaho.