Born in the village of Kalinovik, Bosnia, on March 12, 1942, Mladic was drawn to the military. He became an officer in the Yugoslav People's Army and in 1991 was tapped to lead the 9th Corps against Croatian forces at Knin, according to a BBC profile.
He then became commander of the Yugoslav's Second Military District, based in Sarajevo. When the Bosnian Serb Assembly created a Bosnian Serb army in May 1992, he was appointed commander.
General Mladic was considered one of the key players in the siege of Sarajevo. In 1995, he led the Serb offensive on the U.N.-protected area of Srebrenica, where tens of thousands had taken refuge from earlier attacks.
Serb forces bombed Srebrenica for five days before Mladic entered with camera crews, the BBC reported.
Buses took women and children to Muslim territory while 12- to 77-year-old males were rounded up for "interrogation". An estimated 7,500 Muslim men and boys were killed there from July 13 to 19, 1995.
After the Bosnian war, Mladic returned to Belgrade, where he lived openly -- reportedly going to restaurants and even football matches -- under the protection of former Yugoslav President Slobodan Milosevic. Mladic went into hiding after Milosevic's 2001 arrest.
The International Criminal Tribunal for the former Yugoslavia indicted Mladic and former Bosnian Serb leader Radovan Karadzic -- who has since been captured and awaits extradition proceedings to stand trial at The Hague -- with genocide and crimes against humanity during the 1992-95 Bosnian war.
Milosevic died while in prison in March 2006.
Rasim Ljajic, a Serbian official working with the U.N. tribunal, told the Associated Press in 2006 that authorities uncovered a network of about 130 people, mostly Bosnian Serbs, who have been helping shield Mladic.
Some reports say he might still be in Belgrade and that he is suffering from ill health.