The Red Badge of Courage is an excellent example of Naturalism, a 19th-century literary movement that rejected the conventions of the Romantic period as fanciful and sentimental, focusing instead on depicting reality exactly as it appeared. Influenced by the ideas of Social Darwinism that gained popularity in the late 19th century, many naturalist writers embraced a grim and deterministic view of life, depicting characters who are shaped by their environments and have little power to alter their circumstances. Along with writers such as Theodore Dreiser and Hamlin Garland, Stephen Crane was a leader of this movement in the United States.
At the same time, Crane makes frequent use of impressionism, a literary style inspired by the artistic movement of the same name in which writers focused on a character’s interior life and used imagery to create evocative descriptions of nature. Crane’s frequent personification of the weather and the pastoral environment in which the battle takes place, as well as his choice to stay rooted in Henry’s perspective and relate the young man’s confused thoughts just as they occur to him, are examples of impressionism.
The Red Badge of Courage is also considered one of the first modern psychological war novels. Crane’s choice to focus on one soldier’s mental and emotional experience, rather than the lives of famous generals or the progress of specific battles, was innovative at the time and has since become a mainstream method of depicting war. Many 20th-century war novels, from Erich Maria Remarque's All Quiet on the Western Front to Tim O'Brien's The Things They Carried, would replicate this approach.