Except for his order of execution, "There are no printed or written records concerning him." John Cox, Folk-songs of the South, ch. 35. "The order is on file in "the courthouse at Welch, McDowell Co." He was hanged on January 19, 1894.; The stories in part originated with W. A. McCorkle, governor of West Virginia, from 1893-1893. In 1916, he wrote a letter to Dr. H. S. Green of Charleston, WV. "He (John Hardy) was a steel-driver and was famous in the beginning of the building of the [Chesapeake & Ohio] Railroad." He went on to write that he was a steel-driver on the extension of the N&W about 1872. He goes on, "John Hardy was the most famous steel-driver ever known in southern West Virginia." He..."was reported to be six feet two, and weighed two hundred and twenty five or thirty pounds." "...as one informant told me, he was as black as a kittle in hell." "....he was a great gambler and was notorious for his luck...." "A man of kind heart, very strong, pleasant in address, yet a gambler, a roue, a drunkard and a fierce fighter." The letter contains more anecdotes in the same vein.
Cox collected his song versions between 1913-1923.
Certainly the stuff of legend is here. In some versions he is a steel driver, in some he is not. As noted in a post above, all information was from informants, some of them people who only knew him as a legend.
Is this man the same as John Henry? Opinion is still split. See the long threads on John Henry, especially posts by John Garst who supports another claimant. Much John Hardy information and discussion is in the John Henry threads.