Dragiša Vasić was born in Gornji Milanovac, Kingdom of Serbia on 2 September 1885. He finished primary school and gymnasium in the town before moving to Belgrade to study law. Between 1912 and 1913, he fought in the Balkan Wars as a reserve officer in the Serbian Army and participated in the Battle of Kumanovo and the Battle of Bregalnica. He continued serving with the Serbian Army during World War I and fought at the Battle of Kolubara in November and December 1914. He retreated with Serbian forces through Albania during the winter of 1915 and 1916 and landed on the Greek island of Corfu, from where he was transferred to the Salonika Front. In 1917, he became disillusioned with the Karađorđević dynasty following the Salonika Trial, in which Vasić's cousin, Ljubomir Vulović, was sentenced to death and executed for being a member of the Black Hand.