He studied painting at the Academy of Fine Arts Zagreb and then went on to edit several popular magazines (Kerempuh, Vjesnik u srijedu, Telegram).
He was of Bosnia Herzegovina origin, but mainly lived and worked in Croatia, and was well known in the former Yugoslavia. He was also one of the founders of the prominent theatres Kerempuh (then called Jazavac) and Komedija in Zagreb, and also worked as the intendant at the Croatian National Theatre in Zagreb. He had his screenwriting debut in 1952 with the animated film The Haunted Castle at Dudinci (Croatian: Začarani dvorac u Dudincima), directed by Dušan Vukotić.
In 1961 Hadžić had his directorial debut with Alphabet of Fear (Abeceda straha).
Hadžić also wrote and directed the 1972 film, Lov na jelene, starring Boris Dvornik and the famous Bosnian singer Silvana Armenulić, a subversive thriller-drama about an emigrant suspected of Ustaša activity, which was timely and popular because of its relation to the Croatian Spring. In the early 1980s he effectively stopped making films, and turned to playwriting.
In this period he wrote more than 57 popular plays and had 14 solo exhibitions of his paintings. In the early 2000s he became active in film again, directing a couple of film adaptations of his comedy plays in 2003 and 2005, followed by the war drama Remember Vukovar (Zapamtite Vukovar) in 2008.
He died in Zagreb.