Janko was born in 1779 in Ohrid, in a family of priests. His father came from the village of Donja Belica, close to Struga, where his cousin Cincar Marko Kostić, another leader in the Serbian Uprising was born. After he had murdered a certain Turk, Janko fled northwards and around the year 1800 and settled in Valjevo where he lived as a tradesman. Though his nickname was "Cincar" ("Aromanian“), his roots were Serb. He got the nickname since he came from an area in which a lot of Aromanians lived, and spoke with a dialect.