John was a gun for hire and a horse thief in the late 1800's. It can be assumed that Ward Earp never sent him to hell, because Wynonna recognizes him as a local, meaning he had been around Purgatory before Wynonna's 27th birthday.
As of 2016, he has become one of Malcolm Ramaker's goons. He was part of the plan that included killing Curtis McCready to lure Wynonna home so that they could steal Peacemaker. Their plan fails when Wynonna rigs her motorcycle with explosives and blows John up. Since John wasn't shot with Peacemaker, he was able to survive.