Here is a photo of Johnny Cash’s high school diploma, found in “House of Cash” by John Carter Cash.
“My father’s high school diploma, dated May 19, 1950. He is listed here as “J.R.” and was seldom called anything else until his time in the air force, when some began calling him “John R.”
Johnny’s life consisted of humble beginnings with school, work in cotton fields and music from the family radio being major factors in his life. (p 33, paragraph 6)