 His son was born Leonard J. Hertz and changed his name at the age of seventeen to John D. Hertz, Jr. in honor of his father; John Jr. later became an advertising executive and was briefly married (1942–44) to film star Myrna Loy.John and Fannie Hertz were major figures in Thoroughbred horse racing.They owned a horse farm at Trout Valley near Cary, Illinois, another known as Amarillo Ranch in Woodland Hills, California.