John was born Alvin Henry Kissick, Jr., a son of Alvin Henry Kissick, Sr. and Lula May Simmons. He later became one of three step-children of John Judson Emil Barnum. John's early childhood was spent in Wyoming where a younger brother, Ira James Kissick, and sister, Tressie May Kissick, were born. By 1930 the family had moved to Wichita, Kansas, where Alvin, Sr. was engaged in landscape gardening. John's parents separated and in time his mother married John Judson Emil Barnum and returned to Wyoming, then to northern Arkansas.
At the advent of World War II, John, Jr. was living in Benton Co., Arkansas. He made a trip to San Francisco, California, enlisted in the U.S. Army on 12 November 1942 and served throughout the war.