From January 2015[3] until March 2020,[4] Krstajić served the role of chairman of the board of Bosnian Premier League club Radnik Bijeljina.

Krstajić was born and raised in Zenica, SFR Yugoslavia, present day Bosnia and Herzegovina to a Bosnian Serb mother from Bijeljina and a father from Žabljak, Montenegro.

[5] After playing in the youth teams of Čelik Zenica, Krstajić moved to Kikinda, FR Yugoslavia, present day Serbia in April 1992, following the breakout of the Bosnian War.

According to Krstajić himself, Red Star was interested in him, but as he comes from a family that cheers for Partizan, he decided to sign a contract with his favourite club.

In 2000, Krstajić joined German Bundesliga club Werder Bremen who paid a DM 1.8 million (about €950,000) transfer fee to Partizan.

[11] Krstajić was a part of the Serbia and Montenegro national team "Famous Four" defence, which conceded just one goal during the qualifying for the 2006 FIFA World Cup.

[13] Krstajić began his managerial career as assistant coach of the Serbia national team for the 2018 FIFA World Cup qualifiers.

Krstajić stated that he and Stanojević did not have full control over the sale and acquisition of players during the summer transfer window, which affected the results on the field.