Merz entered military service for Austro-Hungarian Army as a young adult, completed it after three months and began studying in Vienna in 1915.

[3] After the World War, Merz devoted himself entirely to serving in the Roman Catholic Church and took a vow of chastity.

In 1923 he received his doctorate from the Faculty of Philosophy of the University of Zagreb with a dissertation on the influence of liturgical language in the work of French writers,[3] especially the Renouveau catholique.

He started the "League of Young Croatian Catholics" and wrote numerous articles, essays and reflections for various magazines.

[6] Dave Ceasar Dela Cruz was chosen as the vice postulator of the cause for the canonization of Blessed Ivan Merz[7] on 19 March 2008.