Krmar was born in the Croatian town Vinkovci at the outbreak of the Yugoslavian war, his family fled to Boleč, a suburb of Belgrade.

He started playing football in Boleč, later moving to nearby Vinča where he was spotted by scouts and brought to Red Star Belgrade.

Although he passed the complete youth ranks of Red Star, he first played professionally in the Serbian League West with Mačva Šabac, where he stayed for one year.

The next season, he joined the Kragujevac-based team Radnički 1923, with whom he earned a promotion to the highest league of Serbian football.

[2] In his first year in the Serbian SuperLiga, he received minimal playing time and was loaned to Slavija Sarajevo in the Premier League of Bosnia and Herzegovina where he assisted the club in avoiding relegation.

[3][4][5] In the summer of 2012, he joined another Serbian SuperLiga club - FK Smederevo where he spent the full season capping 23 games and scoring 1 goal.

[12] Their participation in the postseason tournament ended in the opening round after a defeat by the Serbian White Eagles.