In 1905, following the death of Pavlos Melas, he rushed to join the Macedonian Struggle. In Macedonia, he adopted the Nome de guerre "Kapetan Nidas" and became a chieftain of an armed band that operated around Florina. On April 15th, 1905, he and his band were surrounded by a force of 200 Ottoman troops. Following the battle that ensued, several Makedonomachoi were killed or wounded while Kalomenopoulos was captured by the Ottoman authorities and condemned to five years imprisonment at Monastir, but managed to escape three years later. He fought in the Balkan Wars of 1912–1913, being wounded during the Battle of Sarantaporo in 1912.