While working as a a special writer for the New York Times Sunday Magazine where he offered poetry, literary essays, and critical reviews of other poets, Kilmer wrote his most famous poem. He later moved his wife and childern to Mahwah, New Jersey, where he resided until his enlistment in the armed forces.
Kilmer enlisted in the New York National Guard at the beginning of World War I and was killed in France by a fatal bullet to the head on a volunteer mission to locate enemy machine gun emplacements. Joyce Kilmer was only 32 years old at the time of his death (July 30th, 1918). For his valour, Kilmer was posthumously selected and awarded the Croix de Guerre (Cross of War) for bravery by the French Republic. Kilmer was buried in the Oise-Aisne Cemetery, Fere-en-Tardenois, France.
His tragic death thrust the budding writer and poet into the World spotlight and Kilmer also became a symbol for the struggle of the World War I soldier. Decades later the Veterans of Foreign Wars found a never logged forested site to honor Joyce Kilmer and dedicated a bronze plaque embedded in a natural boulder to Kilmer in 1936.
Joyce Kilmer never visited his North Carolina memorial forest, now one of only a very few North American protected old growth stands of ancient trees. It is called the Joyce Kilmer Memorial Forest and managed by the United States Forest Service.