Lyubomir Miletich was born in Štip, today in North Macedonia, to a Bulgarian family originally from Edirne (Odrin) in modern Eastern Thrace, Turkey.

His great-grandfather voivode Mile had left Edirne and settled in the Austrian Banat in the early 19th century, where Lyubomir's grandfather Simo was born.

Simo had two sons, Svetozar and Đorđe, Lyubomir's father, who, after briefly living in Bosnia and North Africa, returned to his homeland to become a teacher in Macedonia and northwestern Bulgaria in 1859.

[2] Miletich studied in Sofia and Novi Sad, but finished school in the Zagreb Secondary School for Classical Education in 1882 and graduated in Slavistics from the University of Zagreb and Charles University in Prague, where he was taught by Jan Gebauer.

Miletich become the dean of the Faculty of History and Philology of University of Sofia during the 1903–04 academic year.