Johnny and his hunting pals murder an innocent man that was wandering in Fortune Park. He and his friends go on about how they believe the zombies and survivors are communists sent to destroy democracy. They are determined to cleanse America of these "traitors", one city at a time.
Johnny James is deadly with a sniper rifle and should be dealt with carefully if attempted to be fought using long distance weapons. Up close in melee combat, he will use a bowie knife and is quick. Chuck can take down Johnny using a quick melee weapon (the Driller, Flaming Gloves, and Knife Gloves are all excellent choices) or a firearm from a far.
If you can manage to carry the Freedom Bear (Robot Bear + LMG) and position it between you and Johnny, the bear will fire as soon as the gun is pointed at him. Works particularly well if it is placed on one side of a tall barrier and you're hiding behind it.
The maintainence room near the ladder to Johnny's location has both the items needed to make a rocket launcher, which is surprisingly effective against him: about 30 shots will generally put him down. He might shoot Chuck and cause him to drop it, but it can be retrieved.
Johnny carries a bowie knife for close-in and a sniper rifle for distance fighting, and will switch between them as Chuck gets closer or farther away. This tendency can be exploited, using an LMG or a shotgun: first, open fire on him. While shooting, approach until Johnny pulls out his knife, then back away until he pulls his rifle. Repeat this, while continuing to pour fire into him. With precise timing, you can take him out without giving him a chance to actually fight. You can also use the jumping attack of the Defiler to deal damage to him whilst exploiting this AI pattern.