On 8 April 1915, he was killed at age 33 by friendly fire, when French artillery deliberately shelled and destroyed the hospital where he was being treated.

According to Ian Higgins, "The predominantly Catholic villagers of Landresse were hostile to their local teacher, by definition a servant of the Republic, and who never went to Mass.

Feeling cut off in an alien environment, tired of constantly battling against suspicion, ill-feeling, innuendo, and accusation, Pergaud resigned his post and went to Paris to work in an office.

"[3] In 1907, Pergaud left Landresse and his wife, for Paris, where he joined Leon Deubel, a longtime friend and inspiration.

In Paris, Pergaud suffered through extreme poverty, even as he worked as a clerk and then as a schoolteacher, in an effort to realize his dream of literary success.

His earliest works were collections of poetry that were published at his own expense through a literary review called Le Beffroi.

In 1912 La Guerre des boutons was published, a tale of a play-war between the small boys of two neighbouring villages.

Pergaud's works remain popular in France; La Guerre des boutons has been reprinted more than thirty times.

On the morning of 8 April, Pergaud and other POWs were killed by friendly fire from a French artillery barrage that destroyed the hospital.

La Guerre des boutons has been developed as a film five times: A Paris society, Les Amis de Louis Pergaud, is devoted to study of him and his works.