Martin Patrick Harney, SJ was born on August 4, 1896 in Lynn, Massachusetts to Jennie (Martin) Harney and Martin B. Harney. He attended Sacred Heart and St. Mary's grammar schools and graduated from Lynn Classical High School in 1915. After his freshman year at Boston College, Harney entered the novitiate of the Society of Jesus at St. Andrew-on-Hudson, Poughkeepsie, New York, in 1916. He earned his bachelor and master degrees from Woodstock College in Maryland in 1922 and 1923. His first classroom assignment was as a scholastic at Boston College in 1923, and he was ordained a Jesuit priest at Weston College in 1929. Harney went on to teach history at Boston College from 1930 to 1933, spent one year teaching at St. Bueno's College in North Wales, and returned to Boston College in 1934. He remained on the faculty as a professor of European History and Irish Cultural Studies until his death in 1976.
Harney authored a number of books about the history of the Jesuits and Catholicism and the history of Ireland. His published works include: The Jesuits in History (1941), published on the 400th anniversary of the order, Brother and Sister Saints (1957), Medieval ties between Italy and Ireland (1963), Good Father in Brittany (1964), Magnificent Witnesses (1970), The Legacy of Saint Patrick (1972), The Catholic Church through the Ages (1974), and Families who Followed the Lord (1974). Harney also founded the Blessed Oliver Plunkett Society, a cultural and social club fostering interests in Irish literature, traditions, songs, and folk dance. In 1965, he received a Gold Medal from the Eire Society of Boston, and in 1966 he received the St. Brendan Society Gold Medal Award. He was also a member of the American Historical Association, the American Catholic Historical Association, the American Jesuit Historical Conference (past president), the Irish Historical Society of Dublin, the American Commission for Irish Studies, and Les Amis de Saint Columban of Luxeuil, France.
Martin P. Harney, SJ died on November 10, 1976 at the Campion Center, Weston College.