Kolvenbach's childhood was spent in Druten, near Nijmegen in the Netherlands. There, he attended Canisius College for his secondary studies. At Canisius, he concentrated on modern languages. He entered the novitiate at Mariendaal on 7 September, 1948. After completing philosophy studies at Berchmans Institute in Nijmegen, he was assigned to Lebanon, where he completed his doctorate in Sacred Theology at Université Saint-Joseph in Beirut. Soon after, in 1961, he was ordained a priest in the Armenian Catholic Church, an Eastern-rite church in communion with Rome.