Opposed to the royal absolutism of King Aleksandar I Obrenović, Stojanović joined the People's Radical Party of Nikola Pašić in 1897.

[2] As a founding member and a leader of the Independent Radical Party in Serbia, Stojanović was several times Minister of Education and Religious Affairs (1903, 1904, 1906, 1909), and Prime Minister from May 1905 to March 1906,[3] under the democratic and constitutional rule of King Peter I Karađorđević.

[citation needed] After the First World War Stojanović was one of the founders of the Yugoslav Republican Party and its first president.

Stojanović published the catalogues of medieval Serbian manuscripts and old books in the National Library of Serbia in Belgrade as well as the catalogue of manuscript collection at the Serbian Royal Academy.

A scholar of enormous erudition, energy and determination, Stojanović published 17 volumes of works of Vuk St. Karadžić, the main reformer of the Serbian alphabet, including several volumes of his extensive correspondence.