The title is a play on the phrase "Johnny get your gun", a rallying call that was commonly used to encourage young American men to enlist in the military in the late 19th and early 20th century. That phrase was popularized in the George M. Cohan song "Over There", which was widely recorded in the first year of American involvement in World War I; the versions by Al Jolson, Enrico Caruso, and Nora Bayes are believed to have sold the most copies on phonograph records at the time. Johnny Get Your Gun is also the name of a 1919 film directed by Donald Crisp.
Many of protagonist Joe Bonham's early memories are based on Dalton Trumbo's early life in Colorado and Los Angeles. The novel was inspired by an article he read about the Prince of Wales' visit to a Canadian veterans hospital to see a soldier who had lost all of his senses and his limbs (possibly Ethelbert “Curley” Christian, though he did not suffer severe facial wounds). "Though the novel was a pacifist piece published in wartime, it was well reviewed and won an American Booksellers Award in 1940." (It was published two days after the declaration of war in Europe, more than two years before the United States joined World War II.)