Joe Bonham is the narrator and protagonist of Johnny Got His Gun.The novel takes place after Joe has been severely injured in World War I. Joe grew up in a working class household in Shale City, Colorado in the beginning of the century. Joe's family was not well-off, but he remembers them as having been happy. After Joe graduated high school, the family moved to Los Angeles so Joe's father could look for higher paying work. In Los Angeles, Joe got a job in a bakery, working at night. Joe's father soon died and Joe was eventually sent to war.

The novel takes place after Joe has been injured at the front, where he was serving as an infantryman. As the novel proceeds, Joe realizes that he has lost all of his limbs, as well as his face, leaving him blind, deaf, dumb, and without smell. Joe thinks rarely of his experiences during the war, and when he does, the memories deal with human interactions rather than battle. Joe does not hold himself as a soldier first. Instead, the novel mainly consists of his reminiscences of childhood and his current struggle to remain sane and, finally, to communicate.

Joe is not a hero type. He is unextraordinary in every capacity save the gravity of his injury. His character is meant to be representative of an every-day, young American man. His injury, however, puts him in remarkable circumstances. Unable to fully experience or communicate with the outside world, Joe must live inside his head. The novel occurs fully within Joe's head as well, making the remaining characters quite flat as compared to supporting characters in most novels. Joe understands, with bitterness, that his injury has granted him a status unlike any other man— he exists on the boundary of life and death. Joe's position makes him lonely and sad, yet there is something extraordinary about it as well. Though Joe acknowledges his own importance sarcastically, the novel shows Joe attaining the status of a leader or even a prophet.

After his injury, as Joe slowly learns strategies to fight off his loneliness and the threat of insanity, his political consciousness also increases. He begins to view his war experience and injury in a larger context of modern warfare conducted in the interests of the upper classes. Joe likewise views his treatment at the hands of modern medicine negatively, a pessimism that is confirmed by a hospital official's terse treatment of him through Morse code at the end of the novel. Joe's approach to these issues is characteristically un-intellectual. Instead, he adopts a realist approach with a common sense tone. He debunks various myths, such as the myth that death can be noble. As Joe becomes increasingly disillusioned with his recent experience of war, his memories of his past take on a nostalgic hue. Implicitly, Joe privileges the security and insularity of both his childhood and the past of his countrymen over the brutal inhumanity of modern warfare and medicine.

Joe stands at the absolute center of Johnny Got His Gun but his character is not wholly foregrounded in the novel. Rather, the emphasis rests upon the circumstance Joe finds himself in, and the effects of that circumstance upon his mind and burgeoning political consciousness.