Serbian priest and patriot, the first diplomatic agent of his country in modern times. He is often called Prota Matija, because, as a boy of 16, he was made a priest and, a few years later, became archpriest (prota) of Valjevo.

His father, Aleksa Nenadović, was a local magistrate and one of the most popular and respected public men among the Serbs at the beginning of the 19th century. When the Turkish Janissaries (Janissary) tried to intimidate the Serbs by murdering all their principal men, Aleksa was one of the first victims. This action, however, instead of preventing rebellion, actually provoked the Serbian revolt of February 1804. Nenadović became deputy commander of the insurgents of the Valjevo district (1804) but did not hold the post for long, because the Serbian revolutionary leader Karadjordje sent him in 1805 on a secret mission to St. Petersburg and afterward employed him almost constantly as Serbia's diplomatic envoy to Russia, Austria, Bucharest, and Constantinople. After the fall of Karadjordje (1813), the new leader of the Serbs, Miloš Obrenović (Miloš), sent Nenadović as representative of Serbia to the Congress of Vienna (1814–15), where he pleaded the Serbian cause and forced his hitherto almost unknown people on the notice of Europe.

In his Memoirs Nenadović gives a fascinating account of the course of the first insurrection and of early attempts to establish a native government in Serbia.