Radivojevich was born into a family of Serbian descent in Szentendre near Budapest in the Kingdom of Hungary, which was part of the Habsburg Monarchy at the time. In 1782, he joined the Austrian army as an officer cadet in the "Peterwardeiner" Grenz Infantry Regiment Nr. 9. He fought against the French at the First Battle of Wissembourg in 1793. He became Oberst (colonel) of the "Broder" Grenz Infantry Regiment Nr. 7 and served with distinction during the War of the Third Coalition in 1805. The "Broder" Regiment fought at the Battle of Dürrenstein on 11 November 1805 and at the Battle of Austerlitz on 2 December.