After starting out at his hometown club Sintelon (later known as Tarkett), Beljanski moved to Spain and signed with Arrate in 2008.

He later played for Kriens-Luzern, Frisch Auf Göppingen, Bregenz and Kadetten Schaffhausen.

After spending 12 years abroad, Beljanski returned to his homeland and joined Vojvodina in 2020.

At youth level, Beljanski was a member of the Serbia and Montenegro winning squad at the European Under-18 Championship in August 2004.

At senior level, Beljanski made his major debut for Serbia at the 2012 European Championship, winning the silver medal.