Kolettis studied medicine in Pisa, Italy and was influenced by the Carbonari movement and started planning his return to Epirus in order to participate in Greece's independence struggles.

He remained in Ioannina till March 1821, when he entered Filiki Eteria and left for Syrrako, together with chieftain Raggos, in order to spread the revolution into Central Greece (Rumeli), but his efforts quickly failed because of the rapid reaction of the Ottoman army.

In the First Greek National Assembly, at Epidavros, he participated as the representative of Epirus and in January 1822 he became Minister of Internal Affairs.

After the Second Greek National Assembly, at Astros in May 1823 he was appointed sub-prefect of Euboea and managed to remove Turkish troops off the island.

At the same time, he continued his political activities, resulting in his election as member of the Legislative Body (Νομοθετικόν), a position that he held till 1826.