After his military service, Lartéguy worked as a war correspondent, particularly for the magazine "Paris Match". He covered conflicts in Azerbaijan, Korea, The Holy Land, Indochina, Algeria, and Vietnam. In pursuit of a story at the start of the Korean War, Lartéguy volunteered for the French Battalion and was wounded by an enemy hand grenade during the Battle of Heartbreak Ridge. In Latin America, he reported on various revolutions and insurgencies, and in 1967 encountered Che Guevara shortly before his capture and execution. In the July 1967 issue of Paris Match, Lartéguy wrote a major article entitled "Les Guerilleros", where he wrote: "At a time when Cuban revolutionaries want to create Vietnams all over the world, the Americans run the risk of finding their own Algeria in Latin America."