He was part of the Nenadović family, among which was his brother Prota Mateja, the first Serbian Prime Minister, his father Aleksa Nenadović (1749-1804), his nephew Ljubomir Nenadović, and his uncle Jakov Nenadović. Simeon Nenadović "Sima" was born in 1793, in Brankovina. His father was knez Aleksa Nenadović, and his mother"s name was Jovanka.
The renegade janissaries, known as dahia, took control of the Smederevan Sanjak in 1802, after murdering Vizier Hadži Mustafa Pasha. The four leaders divided the Sanjak, ruling as dictators, also removing the rights granted by Sultan Selim III. In 1804, the jannisaries executed more than 70 prominent Serb nobles, among which were Aleksa (Sima"s father), and Ilija Birčanin. Sima finished Great School in Belgrade, and military school in Vienna.
The slaughter of the dukes triggered the First Serbian Uprising.
Karadjordje was elected as leader. Sima did only participate in the last year of the Uprising, in the battles on the Drina (1813).
He returned to Serbia, immediately with the outbreak of the Second Serbian Uprising (1815). He became a voivode of the Valjevo nahija.
He died in battles against the Ottomans, in Dublje, 26 July 1815 (22 years old).
