Janko was born in Rogača, beneath the Kosmaj. In his youth, he mostly lived in Belgrade with his sister, who was married to a Turk. In this time he learned Turkish, which would benefit him later on. He, however, came to bad terms with his sister's husband and was forced to leave and return to Rogača. In the region, the Uprising was planned and he joined the uprising and was appointed as the knez of one of the former Ottoman nahiyah, and as he was known for being just, prudent and heroic, he quickly became the head commander of the Belgrade nahija. He had a good appearance, and in the assemblies, he was a good speaker, and in the battles, he was a very adaptive, adroit, and heroic chief. He was popular with the people, and his contemporaries called him "prude and heroic Janko". He was one of the most important figures of the First Serbian Uprising.
He participated in all battles since the beginning: Belgrade, Požarevac, Rudnik, Vrbica, etc. He, Vasa Čarapić and Sima Marković commanded 4,000 soldiers that besieged Belgrade.[2] Karđorđe sent him to the fighting in Mačva, in 1806, as help. He showed great skills, and after the burning of the Sovljak village, he killed 65 Turks and took what they had confiscated earlier. He died while fighting the Ottomans around Šabac, in the village of Krnić, just before the Battle of Mišar.
His death was a huge loss for the Serbian revolutionaries. Although he was a close friend of Karađorđe, he was part of the political group that sought to tackle the Vožd's autocracy. Several more revolutionaries came from his family. His brother Jakob Katić was also a freedom fighter, a revolutionary.
