Brkić was born on 16 July 1913 in Livno where he attended elementary school. He attended gymnasium in Bihać, Banja Luka and Sarajevo. After graduation from high school, Brkić attended Law School at the University of Belgrade where he graduated in 1937. During his high school days he was a member of the Communist Party Youth. During his student days in Belgrade he was prominent in leading the circles of the Revolutionary Students' Movement. He became a member of the Communist Party of Yugoslavia in 1933. As a representative of the University of Belgrade, he participated, along with Ivo Lola Ribar and Veljko Vlahović, on the Congress of World Federation of Students in Prague in 1936. Because of his communist activities during the study, Brkić was repeatedly arrested by the police.
Communist activity
After he finished his study Brkić went to Sarajevo and became employee of the "Agrarna banka". Soon after he arrived in Sarajevo he made a connection with the Communist Party and again became politically active. Due to his communist activity he was fired from the service in bank, later he found a job as a municipal official, after which he worked as a law clerk. From 1938 along with attorneys of the Central Committee of the Communist arty, he worked on the development and consultations of the organisations of Communist Party in Bosnia and Herzegovina. Brkić also participated in Fourth Regional Conference of the Communist Party of Yugoslavia for Bosnia and Herzegovina held in Mostar in 1938. In 1940, he became a secretary of the Sarajevo District Committee for the Communist Party of Yugoslavia.
World War II
When the invasion of Yugoslavia started in April 1941, Brkić was mobilized to the Royal Yugoslav Army. When Kingdom of Yugoslavia capitulated, he was in service in Sinj. After that he returned to his hometown where he worked in local organisation of the Communist Party of Yugoslavia. Soon he went to Sarajevo and started with organising of the rebellion in Bosnia and Herzegovina. He participated in session of the Regional Committee of the Communist Party for Bosnia and Herzegovina held on 13 July 1941, where Communist Party made decisions about the rebellion against the Axis forces. On this session he became a commander of the Headquarters of Partisan detachments of Sarajevo District and he also participated in the creation of earliest partisan detachments: Romanija detachment, Kalink detachment and Detachment "Zvijezda". During the war, he held various posts, he was political commissar of Partisan Detachment "Zvijezda", deputy of political commissar of the 6th Proletarian East Bosnian Shock Brigade and a political commissar of the 27th East Bosnian Brigade. He was a councilor of the AVNOJ from November 1943 to 1945 and secretary of the ZAVNOBiH. During the war he was chosen as member of the Regional Committee of the Communist Party of Yugoslavia for Bosnia and Herzegovina and secretary of the Districts Committee for the Eastern Bosnia. Even though he was a high-ranking party member during the war, he was often in contact with the enemy. In battle against the Ustaše in Han Pogled near Han Pijesak he distinguished himself by capturing an Ustaše's stronghold. He was also successful in battle against Chetniks on Vareš railway where he, alongside Pero Kosorić, completely annihilated them.
