Born in Abu Dhabi, to Bosnian Serb parents, he chose to represent Serbia in the international swimming competitions.

After a brief six-month training regimen under Tidey, Stjepanović won his first medal, a bronze, at a competition in England.

At the 2013 Mediterranean Games held in Mersin, Turkey he won the gold medal in 200m and 400m freestyle and 200m butterfly.

At the 2014 FINA Short Course World Championships in Doha, Stjepanovic won a bronze medal in the 400m freestyle.

http://www.swimstar2000.net/all/doha/Doha-2014-SRB.htm [5] Stjepanovic was a member of the inaugural International Swimming League (ISL) representing DC Trident.