Born in Prinkipo, Constantinople (Büyükada, Istanbul) in 1952, he studied in his home city until he was obliged to quit after the closing of the Theological School of Chalki in 1971 in order to continue his interrupted studies at the Faculty of Theology of the Aristoteleion University of Thessaloniki. Subsequently, he followed courses in the Ecumenical Institute of Bossey, the Faculty of Theology of Geneva University and the Faculty of Theology of Fribourg University. He holds a MA from the Faculty of Theology of the Aristoteleion University of Thessaloniki. He served at the Orthodox Centre of the Ecumenical Patriarchate, in Chambésy, Geneva, as research assistant (1975–1987), participating actively in the preparation of inter-orthodox, inter-Christian and inter-religious meetings, in the organization of theological seminars for the younger generation (developed later into the Institute of Orthodox Theology in collaboration with the theological faculties of Geneva and Fribourg) and in the publications of the Orthodox Centre resulting from its manifold activities.
He joined the staff of the World Council of Churches, where he served for thirty years (1987–2017), first, as executive secretary for Orthodox studies and relationships in mission (1987–1993), then, as executive secretary for church and ecumenical relations, being responsible for relations with the Orthodox member churches and the Roman Catholic Church (1993–1998). He was elected by the central committee to serve as deputy general secretary (1998–2017), one of his responsibilities being to coordinate the staff group serving the Special commission on Orthodox participation in the WCC and, later, the Permanent committee on consensus and collaboration.
While serving as deputy general secretary, he was entrusted by the Ecumenical Patriarchate the responsibility of serving as Permanent representative of the Ecumenical Patriarchate to the WCC (2007–2015).
His All Holiness Ecumenical Patriarch Bartholomew granted him one of the honorific offices of the Ecumenical Patriarchate (Άρχων Μέγας Ιερομνήμων).
He is the author and editor of books in Greek and in English, while many of his essays were published in several reviews, mostly in European languages.