Niko was born in Yugoslavia and grew up in Bosnia. His father was a bully who never believed in whilst his mother, Milica, was unhappy that her son grew up in such a harsh place. He had a brother who was killed, although it is not stated how or when. He had wanted to be an astronaut but in the war-torn Bosnia this was impossible.
He fought during the Bosnian War as an "angry" teenager, where he witnessing and committing numerous atrocities, leading to his cynical view on life. Niko was almost killed in 1998 when the fifteen man unit he was in were ambushed, with twelve of his friends killed in the attack. Only he, Florian Cravic and Darko Brevic, who had betrayed the unit, survived. He knew that he was not the betrayer, so the only two options were Darko and Florian.
Post War Life
Work was hard to come by following the war, although Niko did not leave, working in the criminal underworld for the next ten years. He also continued his search to discover who ambushed his army unit, until his arrest. After being released from prison, he began working for a human trafficking ring under the orders of Rodislav Bulgarin. When a boat sank in the Adriatic during one smuggling run into Italy, Niko managed to swim to safety, although everything else was lost. Rodislav Bulgarin blamed the sinking on Niko, stating he had sunk the ship intentionally to escape with the money. Bulgarin was too powerful to fight back against and so he joined the merchant navy.
Life in Liberty City
He spent seven months at sea on the Platypus ship, heading for Liberty City, where his cousin Roman lived. Niko also knew that Florian Cravic had moved to the city. He arrives in Liberty City in 2008 and realises that Roman's tales of success are lies as Roman only owns a small flat, a taxi depot and has large gambling debts. Niko ends up working for Roman, protecting his cousin from the loan sharks that keep harassing him. Roman soon loans Niko's services to friends and enemies alike, which angers Niko although he needs the money, and sets in motion the events of the game.
Niko's view of American culture is one of confusion and mild disgust. The rampant materialism annoys him and he has trouble relating to Roman's fascination with the country. Plus, after working for so many criminals, he feels that everyone in Liberty City is a crook.
At the end of the game, a Weazel News report states that Niko is wanted for questioning by the police.