Born in Ballylongford in 1921, he became a Jesuit priest, did a doctorate in archaeology and Semitic languages in Belgium's Louvain University, worked on the famous Dead Sea scrolls, participated in archaeological digs in Egypt and served as private secretary to a Vatican cardinal, among many other achievements.His 1999 obituary in the Independent (UK) gives additional details:
Martin grew up in a large, traditional Catholic family in County Kerry and in 1939 as a young man entered the Jesuit Order. He read for a BA in humanities at University College, Dublin, then spent three years studying philosophy followed by three years teaching in a Jesuit college in Ireland, and four years of theology studies at Milltown Park, Dublin (the college where Jesuits did their theological training). There he was ordained into the priesthood in 1954, taking his final vows as a Jesuit on 2 February 1957.And then, of course, his life took a rather different direction. He is best known as the exorcising priest in the episode on which the 1973 movie The Exorcist is based.
His talents were soon apparent and he was sent for further studies outside Ireland. He received doctorates from the universities of Louvain and Oxford and from Hebrew University in Jerusalem, where he concentrated on knowledge of Jesus as transmitted in Islamic and Jewish sources. As a biblical scholar, Martin's main contribution was the book The Scribal Character of the Dead Sea Scrolls, published in Louvain in 1958.
Marked out as a high-flyer, he became Professor of Palaeontology and Semitic Languages at the prestigious Pontifical Biblical Institute in Rome and was a theological adviser to Cardinal Augustin Bea, the head of the Vatican's Secretariat for Promoting Christian Unity. This brought him into close contact with Pope John XXIII.
Martin's years in Rome coincided with the start of the Second Vatican Council (1962-65), which was to transform the Catholic Church in a way that the initially-liberal Martin began to find distressing. Disillusioned by the reforms taking place among the Jesuits, the Church's largest religious order, Martin requested a release from his vows in 1964 and left Rome suddenly that June.
Amusingly, in the quote from the obituary his academic title is given as "Professor of Palaeontology." That should be Professor of Palaeography.