Johnny Christ attended Marina High School in Huntington Beach, California. He proceeded through high school and eventually formally met M. Shadows, Zacky Vengeance, Synyster Gates, and The Rev (the latter of the two which he already knew from school). He is also friends with Zacky Vengeance's younger brother Matt Baker formerly from the band The Dear & Departed. In May 2009 he participated in the Gumball 3000 Rally, driving coast to coast with the Fuel Girls.
Johnny initially took a few weeks off from high school during his senior year to fill in for Avenged Sevenfold's previous bassist, Dameon Ash, during one of their tours. These few weeks would become permanent as Johnny dropped out of high school to become the band's current bassist. When the band was practicing in M. Shadows's parent's garage, Johnny would walk down the street and tell them that their bassist was inadequate and that they should let him play with them instead. His two biggest influences are Cliff Burton (now deceased bassist for Metallica) and Duff McKagan (the bassist from Velvet Revolver and formerly Guns N Roses). The person that inspired him the most to pick up a bass was Les Claypool, the bassist and vocalist from Primus.
Johnny first recorded on their second album Waking the Fallen. He used to write only Johnny on his autographs until Zacky came up with the name 'Johnny Christ', and in All Excess he said, "That sounds... really [audacious]. Everyone's gonna hate that, so... I should definitely go with that!"