Born in 1960 in Klagenfurt, Austria, Johannes Modesto studied Catholic Theology and Latin and Greek Philology at the university of Monaco (Ludwigs-Maximilians-Universität München).
In 1988, he graduated with a degree in Theology with a thesis on Gregorio Magno, successor of Peter and Universal Primacy.
Since 1989, he has worked as a pastoral employee for the Archdiocese of Monaco and Frisinga in many areas (ecumenism, personal employee of the Vicar General, management of priests).
Since 2016, he has been the Postulator for the cause of Beatification of Romano Guardini and Fritz Gerlich.