Stephanides served as a gunner in the Greek army on the Macedonian front in 1917–1918. Following that, he participated in the Greco-Turkish War of 1919–1922. Subsequently, he would write "Macedonian Medley; 1917–1918", an account of his participation in the Macedonian campaign, based on a diary he kept during that time. For 18 months, he served in a relatively calm and stable area, south of Ghevgheli and near the towns of Kilkis and Isvor. He often acted as a liaison with British and French units, owing to his knowledge of English and French.