Archbishop Diarmuid Martin was born in Dublin on 8th April 1945. He attended schools in Dublin (Oblate School, Inchicore; De La Salle School, Ballyfermot; Marian College, Ballsbridge). He studied philosophy at University College Dublin and theology at the Dublin Diocesan Seminary (Holy Cross College, Clonliffe).
He was ordained priest on 25th May 1969. He later pursued higher studies in moral theology at the Pontifical University of St Thomas Aquinas (Angelicum) in Rome. In 1973-74 he was Curate at the Parish of St Brigid in Cabinteely. In 1975 he was responsible for the pastoral care of Dublin pilgrims during the Holy Year in Rome.
He entered the service of the Holy See in 1976 in the Pontifical Council for the Family. In 1986 he was appointed Under-Secretary of the Pontifical Council for Justice and Peace, and in 1994 Secretary of the same Pontifical Council. On 5th December 1998 he was appointed Titular Bishop of Glendalough and received the Episcopal ordination at the hands of Pope John Paul II in St Peter’s Basilica on 6th January 1999.
During his service at the Pontifical Council for Justice and Peace, Archbishop Martin represented the Holy See at the major United Nations Conferences on social questions in the 1990s. He also participated in activities of the World Bank and the International Monetary Fund, especially on the theme of international debt and poverty reduction.
In March 2001, he was elevated to the dignity of Archbishop and Apostolic Nuncio and undertook responsibilities as Permanent Observer of the Holy See in Geneva, at the United Nations Office and Specialised Agencies and at the World Trade Organisation. He was appointed Coadjutor Archbishop of Dublin on May 3rd 2003. He succeeded Cardinal Desmond Connell as Archbishop of Dublin on 26th April 2004.