Pozaić was born into a Croatian Roman Catholic family of Janko and Agata (née Salar) near Marija Bistrica in the Hrvatsko Zagorje region.

After finishing primary school, which he attended in his native Selnica and Bedekovčina and graduation at a classical gymnasium in Šalata, Zagreb, he joined a religious order of the Society of Jesus and after the novitiate consequently studied at the Philosophical and Theological Institute of the Society of Jesus in Zagreb.

[1] He professed as a Jesuit and was ordained as priest on 24 June 1973,[2] after completed his philosophical and theological studies.

On 19 March 2005, he was consecrated as bishop by Cardinal Josip Bozanić and other prelates of the Roman Catholic Church in the Cathedral of Assumption of Blessed Virgin Mary and St. Stephen of Hungary in Zagreb.

[2] Pozaić resigned as an Auxiliary Bishop on 13 May 2017 before reaching the age limit of 75 years old, because of a health reasons.