[2] His mother was a teacher in Dugo Selo, and his father a sea captain who authored one of the first naval dictionaries in the Kingdom of Yugoslavia.

Crnić attended elementary school in Dugi Selo, after which he enrolled in the elite Classical Gymnasium in Zagreb.

It was unclear to many of his colleagues why he, as a renowned legal expert, accepted a position on the, at the time, highly polarized Constitutional Court whose members didn't even have to be lawyers.

Crnić was also a Managing Director of the Adris Foundation[6] and President of the Administrative Council of the Croatian News Agency.

In addition, he is a founder and first editor of one of the oldest local newspapers in Croatia "Dugoselske kronike" (Dugo Selo Chronicles).

[4][7][8] Crnić was the honorary president of the 100th anniversary of the "Preporod" Cultural Arts Society from Dugi Selo, the winner of the annual Dugi Selo Lifetime Achievement Award in 1996, honorary citizen of Fužine and Mrkopalj Municipalities and the town of Senj, Knight of the Order of Saint Lazarus, a member of the Brethren of the Croatian Dragon, and General Major in the Legal Service of the Armed Forces of Croatia.