Leonard was married to Beverly Cline from 1949 until they divorced in 1977.[1] Then he was married to Joan Shepard from 1979 until her death in 1993.[1] Then he was married to Christine Kent from 1993 until his death in 2013.[1] He had five children with Cline.[1]
Leonard spent the last years of his life with his family in Oakland County, Michigan. He suffered a stroke on July 29, 2013. Reports stated that Leonard was recovering from the stroke.[2]
On August 20, 2013, Leonard died at his home in Bloomfield Hills (a Detroit suburb) of complications from the stroke.[3] He was 87 years old.[4]