Ms. Antoljak-Kostadinov has worked at the Croatian Heritage Foundation (Hrvatska Matici Iseljenika) since 1992 starting as a staff writer for Matica and was responsible for matters related to the Croatian diaspora. Today she project manages initiatives in the cultural department. In addition, Ms. Antoljak–Kostadinov leads the ECO Heritage Task Force, a project that offers youth of Croatian descent the world over an opportunity to visit and experience Croatia while studying its language, culture and history. She is the custodian of numerous cultural manifestations and artistic exhibits that feature Croatia and its artists throughout Croatia, Bosnia-Hercegovina, and around the world. Noteworthy projects include amateur theatre productions and the festival of folk theatre and the Croatian Film Festival in Orašje, BH.