[1] Initially a police officer under the leadership of local governor Jovan Obrenović, he began his political career in 1842 during the rebellion led by Toma Vučić Perišić.

[1] His heavy-handed approach to politics led to Blaznavac being outmaneuvered by another member of the regency, the moderate liberal Jovan Ristić, and his staunchly pro-Austrian foreign policy was somewhat curbed as a result.

[2] After Prince Milan came of age in August 1872, Blaznavac shortly served as head of government before his sudden death in April 1873.

At the time, a rumor circulated that he was an illegitimate son of the prince, who married off one of his concubines to a struggling village storekeeper with a generous dowry after she became pregnant.

He intercepted and destroyed a written order sent out from Belgrade to the governors of the districts of Čačak and Užice to come to the aid of Prince Mihailo.

He gained the prince's trust and reported on his plans to take advantage of the revolutions of 1848 to cross into Serbia and stage a coup.

During the Crimean War, Blaznavac took part in several diplomatic missions in Vienna, meeting with ministers Buol and Bach, as well as Russian ambassador Alexander Gorchakov.

[1] When the Assembly voted Prince Miloš Obrenović back into power in 1858, Blaznavac was in favor of staging a coup to protect the Karađorđević dynasty.

From there, he wrote to the governor of the Belgrade fortress Sherif Topal Osman Pasha in 1859 detailing his plans on how the Porte could depose the Obrenović dynasty and restore Serbia as a loyal province of the Ottoman Empire.

Blaznavac exploited the power struggle that emerged between her mother Anka and Ilija Garašanin, relaying information from both sides as a double agent, as well as to the prince himself.

Ristić was also successful in curbing Blaznavac's staunchly pro-Austrian foreign policy and creating deeper ties to Russia, with the goal of balancing between the two.

However, Slobodan Jovanović records his cause of death as Ludwig's angina, a curable condition which was probably left untreated by his insufficiently educated doctor.

In Because My Thoughts Are Struggling (2023), a historical drama film directed by Milorad Milinković, Blaznavac is portrayed by Nebojša Dugalić.