After several Turks abducted his sister Teodora, Janko, a young and courageous man, with several comrades chased them down and killed them.

As it was unsafe for him to remain in his home region, he moved to the village of Boleč between Belgrade and Grocka.

He joined the Serbian Free Corps and participated in the Austro-Turkish War and Koča's frontier rebellion, where he gained military experience.

Known for his bravery, he was chosen to be a knez (village chieftain) in Boleč during the Habsburg occupation of Serbia.

Janko was unreluctant in attacking Dahije but controlled a road to Smederevo near Boleč along with his comrades.