The Jeličić family originally lived in Kordun, in present-day Croatia, but emigrated as refugees to the Serbian town of Šabac, hoping for a better life there.

[2] As the Austro-Hungarian Army approached Belgrade, he participated in the attempts to defend the Serbian capital against the invading forces.

[1] In Niš, he befriended Archibald Reiss, a professor in criminology who later would become known for his documentations of Austro-Hungarian war crimes against civilians during the occupation of Serbia.

[2] Shortly before the age of fourteen, he was promoted to Lance Sergeant, and he participated in the battles at the Salonika front.

[1][3] During the Axis occupation of Yugoslavia in the Second World War, he joined the Yugoslav Partisan resistance movement.