He became a career NCO (non-commissioned officer), and fought in the Greco-Turkish War of 1897 as a sergeant.[1] After studies in the NCO school, he was commissioned an officer as a 2nd lieutenant of artillery.[1] In 1908 he was sent to Crete, to help organize the local militia.[1]
Following the victory of the royalist opposition in the November 1920 elections, he was placed on leave, and only recalled to active service after the collapse of the Greek front in Asia Minor and the September 1922 Revolution.[1] He helped organize the Army of the Evros, and served as its chief of staff.[1]
He resigned from the Army in August 1923 with the rank of major general,[1] 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.
He then entered the political arena, and was elected a Member of Parliament for Athens,[1] a post to which he was continually re-elected until December 1930. In 1930 he became Minister General-Governor of Thrace, contributing to the organisation of Western Thrace.