Johnny is an original character and one of the antagonists of The Walking Dead Season 2 Episode 2: A House Divided and part of Carver's group.
Johnny alongside Carver, Bonnie and Troy headed to the Moonstar Lodge and was armed with AK-47's. After killing the Walkers and saving the survivors, Johnny and the others took the group hostage while Carver ordered to have Luke, Kenny, Rebecca, Alvin and Clementine tied up with the group. Bonnie ordered Johnny to guard the window. However, Kenny managed to shoot Johnny in the head with his rifle, instantly killing him.
In revenge, Carver took Walter and shot him in the head, killing him too.