Second Hellenic Republic
He resigned from the Army in August 1923 with the rank of major general, and settled in Athens, where he witnessed the royalist Leonardopoulos-Gargalidis coup attempt. Kalogeras formed a force of 3000 volunteers in Athens, and participated in the suppression of the coup in Macedonia and Epirus. Thus, he contributed to the fall of monarchy and the declaration of the Second Hellenic Republic.