Upon outbreak of the World War I, he moved to Niš, Serbia and joined the censorship office of the Royal Serbian Army.

He was a member of the Yugoslav Committee, an ad-hoc group of politicians and activists supporting political unification of the South Slavs in 1915–1919, and a representative of the newly established Kingdom of Serbs, Croats and Slovenes at the Paris Peace Conference in 1919–1920.

Županič joined the People's Radical Party and became the president of its regional committee for Slovenia.

[1] Županič was the founder and the first principal of the Ljubljana-based Slovenian Ethnographic Museum (in 1923).

In 1926, he started publication of ethnological journal Etnolog in Ljubljana.