He was born in Corfu in 1861, a descendant of a branch of the Albanian Dushmani family that had emigrated to the island in the 15th century; he is the elder brother of Sofoklis Dousmanis and grandson of Antonio Dusmani. He entered the Hellenic Army Academy, from which he graduated on 11 July 1883 as an Engineer 2nd Lieutenant. Promoted to Lieutenant in 1886 and Captain in 1890, he participated in the Greco-Turkish War of 1897 as an officer in the staff of the Army of Thessaly under the Greek Commander-in-Chief, Crown PrinceConstantine. After the war, he was charged with writing the official report. In 1899–1904, he served as section head of the Staff Service of the Greek Ministry of Military Affairs, and in 1904, with the foundation of the Army General Staff, he was transferred to the newly created General Staff Corps. Among his duties there was the organization of the National Defence Fund. He was promoted to Major in 1906 and Lt. Colonel in 1909. During the First Balkan War of 1912–1913 against the Ottoman Empire, he was chief of operations for the main Greek force, the Army of Thessaly, again under Crown Prince Constantine. In the Second Balkan War against Bulgariain the summer of 1913, he served as chief of staff to the field army, again under Constantine, who had by now become King. In the same year, he was promoted to Colonel and then to Major General. In early 1914 he was appointed Chief of the General Staff Service, but resigned in November after a quarrel with Prime Minister Eleftherios Venizelos over the issue of Greece's entry into World War I. Venizelos favoured siding with the Entente Powers, especially Britain, for the upcoming Gallipoli Campaign while Dousmanis, a believer in the victory of Germany, advocated neutrality. In February 1915, however, Venizelos was forced to resign over the same issue by King Constantine, and Dousmanis resumed his post, which he held until mid-August 1916. Having sided with Constantine during the National Schism, in June 1917, when Venizelos assumed the governance of the country and led it to war on the side of the Entente, Dousmanis, along with other prominent royalists, was deported to Corsica. Returning to Greece after the end of the war, in 1919 he was sentenced by a Venizelist court martial to life imprisonment for high treason. Following Venizelos' downfall in the November 1920 elections, he was released from prison, and, promoted to Lt. General, he was re-appointed as Chief of the General Staff in April 1921, during the Asia Minor Campaign against Turkey. He held this post until October 1921, and again from 22 August 1922, when the Greek front in Anatolia collapsed in the face of the Turkish offensive, until 15 September, when he was forced to resign along with the government by the Venizelist-led 11 September 1922 Revolution from the defeated Greek troops. He was permanently discharged on 2 November 1922, and dedicated his last years to writing on military and historical issues. He died in 1949. He was awarded Serbian Order of the White Eagle and other decorations.
