Fussell died of natural causes at a long-term care home in Medford, Ore., his stepson, Cole Behringer, told The Philadelphia Inquirer.
Fussell's education was interrupted by World War II, where he won Bronze and Silver Stars and a Purple Heart in Europe. He graduated from Pomona College after the war and went on to earn a doctorate in English literature at Harvard.
His best-known work, published in 1975, was an examination of World War I and its myths. "The Great War and Modern Memory" won a National Book Award and Book Critics' Circle Award.
Fussell taught at Connecticut College and Rutgers before he moved to Penn about 30 years ago. He retired in the early 1990s.
In his later years, Fussell wrote books like the 1991 "BAD: or The Dumbing of America," which took a dim view of the modern United States.
"What he likes about the United States would fit comfortably under a gerbil's paw," critic Christopher Buckley said in The New York Times, telling readers that "when the Jeremiad is Paul Fussell, attention must be paid."
In addition to his second wife, Fussell is survived by two children from his first marriage and four stepchildren.