He was a Confederate civil war veteran and fought under the command of General J.E.B Stuart
Jack eventually wound up in Kansas in the late 1870s. He went to Tombstone, Arizona, from Dodge City, Kansas, where he possibly previously knew the Earps and also perhaps Doc Holiday He was listed by Virgil as special policeman (i.e., deputy city policeman) June 22, 1881. This is the day of the large Tombstone fire of 1881, with which Virgil had to cope as acting city marshal; the date suggests that Jack is one of the extra men Virgil hired to help cope with looting, during and after the disaster.
The origin of Texas Jack, Vermillion’s nickname, is unknown, but he is first listed by this moniker on a wanted poster, for shooting a man during an argument at cards. When asked about why he was called Texas Jack, he replied “Because I’m from Virginia.”
Vermillion did not accompany Virgil Earp as a member of the protective squad which escorted him to Tucson, March 20, 1882. Instead, Vermillion joined the vendetta posse March 21, 1882 in Tombstone, a day after the killing of Frank Stilwell in Tucson, thus Vermillion was not one of the 5 men indicted for Stilwell’s killing. Vermillion may have participated in the Earp posse more as friend of Holliday, who was also a Methodist and fellow southerner. Note that Holliday’s father had also served as a Confederate soldier.
He returned to Virginia 1890. Being a Virginian it is believed he got the nickname Texas Jack because he preferred to ride horses from Texas.
From: The Civil War Parlor on Tumblr