By that time, Greece was embroiled in the Greco-Turkish War of 1919–1922 against Kemal Atatürk's Ankara-based Turkish nationalist movement. In early 1921, Kontoulis replaced the Venizelist general Konstantinos Nider in command of I Army Corps. During the March 1921 offensive, he was successful in breaking through the Turkish lines at Dumlupınar and capturing Afyonkarahisar. The defeat of III Army Corps in the northern sector of the offensive (First Battle of İnönü) forced him to withdraw back to the Dumlupınar lines. There he repulsed repeated Turkish assaults on 26–29 March. Kontoulis led the I Corps again with success during the Greek summer offensive, during the subsequent march through the salt desert around Lake Tuz towards Ankara, and in the decisive Battle of the Sakarya and the subsequent Greek retreat. He was named Lt. General on 6 October 1921, and in May 1922, he was replaced as commander by Lt. General Nikolaos Trikoupis, returning to Greece, where he went into retirement on 24 April 1923.