Career
In international competition he has represented Serbia. Early career
After spending many years of his youth playing with Red Star Belgrade, during which he was loaned to FK Jedinstvo Ub, he decided to accept a challenge that came from Belgium and moved to Lierse South.K. in August 2005. In the summer of 2006, he was loaned to another Belgian First Division club, South.V. Zulte Waregem before moving to Russia to play with Premier League club Football Club Khimki.
Vojvodina
After one season in Russia, he returned to Serbia to join FK Vojvodina in the Serbian SuperLiga.
In spite of arriving to the club off of dry spells in Belgium and Russia, he became Vojvodina"s captain after a remarkably short period of time due to a spontaneous explosion of good form. His prolific goal-scoring with Vojvodina earned him calls from the Serbian national team from 2008, having been called up for a friendly against Bulgaria and another friendly match against Austria which took place the same year.
Sion
After two seasons spent in Novi Sad, in summer 2010, he signed a 3-year contract with Swiss side Football Club Sion. In March 2011 in a match against Football Club Zürich he suffered a serious knee injury which kept him out of football for six months.
Return to Red Star Belgrade
After seasons spent in Sion, Mrđa returned to the club at which he debuted professionally, signing a two-year contract with Red Star Belgrade.
Omiya Ardija
On July 1, 2014, Mrđa joined J. League Division 1 club Omiya Ardija. Mrđa scored on his debut on 19 July 2014 helping them to earn a 3–3 draw against Sanfrecce Hiroshima. He played 18 times for Omiya in the 2014 as they suffered relegation to the Division 2.
Mrđa was a part of the Serbian U21 team that made it to the final of the 2007 Union of European Football Associations European Under-21 Championship, where he scored coming off the bench against the Netherlands U21 side.
By the end of the championship he had scored a total of two goals, which was on level with the likes of Ryan Babel.