 In 1913, Sarris participated in the battle to capture Bulgarian troops stationed in Thessaloniki and was decorated with the silver knight's cross of the Battalion of Saviour for his services in liberated Thessalonica.In 1916, along with other citizens and officers of Macedonia, Sarris took part in the creation of the Committee of National Defence.In August 1916, as commander of the first company, he participated in the National Defence coup d’ etat that intended to spur Greece's entry in World War I in favour of the entente powers.