He was later commissioned and participated in the Macedonian Struggle (1904–1908) leading his own guerrilla band, and was promoted to captain during the Balkan Wars (1912–1913).

He was notorious for his cruel oppression of a loyalist revolt in Chalkidiki (Sept 1916),[1] rising to the rank of lieutenant colonel.

He returned after the 1922 Revolution as a major general, suppressed the royalist revolt of 1923, retired from the army, and became involved in politics.

On 24 August 1926, he overthrew the dictatorship of Theodoros Pangalos in a bloodless coup and formed a government, proclaiming elections for November.

Later that day, Kondylis forced Zaimis to resign, declared himself Regent, abolished the Republic and staged a plebiscite on 3 November for the return of the monarchy.

The official tally showed that 98 percent of the voters supported the return of George II—an suspiciously high total that was likely obtained through fraud.

His nephew, Georgios Kondylis Jr., became a general in the Hellenic army and later fought against the Axis during the German invasion of Greece.