Miljuš has started playing football in academy named "Fitness" in Kragujevac at the age of 6, along with his twin brother Dejan. After 5 years, they moved to the local Radnički. After he passed youth categories, Miljuš was loaned as a scholar to the Serbian League West side Pobeda Beloševac, where he was trained by Željko Milošević, former defender, and captain of Radnički Kragujevac.[2] Playing with Pobeda, Miljuš noted 25 league appearances between 2013 and 2015.[3]
Around a year after he was born, the Miljuš family moved from Knin to Kragujevac, due to Operation Storm. His twin brother, Dejan, is also a footballer.[2]