Dionysios was born in Halkidona in 1916. Following initial studies in Halkidona, he was educated at the Great Patriarchal Clergy School in Fanar. In 1934 he entered the [[Theological School of Halki]], graduating in 1941. As soon as he graduated he was [[ordination|ordained]] [[deacon]] and served the Tataouli Community of Constantinople. In October 1945 he was ordained [[presbyter]], and was elevated the following month to the office of [[archimandrite]], serving as [[vicar]] and Chief Education Officer of Halki's Holy Theological School.
In October 1947 he was transferred to London, where he served at vicar of the Cathedral of Holy Wisdom. For twelve years he was the secretary of the Ecclesiastical Court of the Archdiocese of Thyateira.
In 1959 he was elected by the Holy Synod of the Ecumenical Patriarchate as Bishop of Nazianzos and designated as assistant to the Archbishop of Australia. In 1970 the Ecumenical Patriarchate determined to restructure Asia and Oceania by creating a new Metropolis for all parishes in the region outside Australia. Bishop Dionysios was elected on January 8, 1970, as the first Metropolitan of New Zealand, with his see at Wellington. In this role, the Metropolitan was responsible for the growth of the church in rapidly growing mission areas such as the Philippines, Indonesia, and Korea.