Bradonjic was born on December 11, 1999, in Priboy, former Yugoslavia. He joined the Radnik Academies and reached the first team with which he made his debut at the age of 17.

Until January 2021, Bradonjic had made 72 appearances, scoring 16 goals, while also contributing three assists, arousing the interest of PAOK, with the club opting to acquire him on a four-year deal.

Bradonjic, despite once playing for the Serbia Under-19 side, opted to switch and play for Bosnia and is now a member of their Under-21 squad, with whom he has played three times.