[2] Grgić was born into a Bosnian Croat family[2] in Novo Selo, Kotor Varoš in Bosnia and Herzegovina, then a constituent republic of Yugoslavia.

Starting his career in his native Roman Catholic Diocese of Banja Luka, he served as chaplain in Stara Rijeka until 1987 and then as vicar in Glamoč from 1987 to 1988.

[1] When the Yugoslav Wars between Catholic Croats and Orthodox Serbs erupted in 1991, Grgić was teaching at a seminary in Zadar, Croatia.

Grgić became a war refugee in August 1995 when Bosnian Serb authorities which controlled Banja Luka drove him out along with his parishioners.

[1][2] Grgić worked at St Sunniva School and as chaplain at St. Olav's Cathedral, Oslo, from 2000 and 2001 respectively before leaving Norway shortly for the Roman Catholic Archdiocese of Munich and Freising in 2007.