His Holiness was born in 1932 in Mosul, Iraq. He completed his high school education at St. Thomas Syrian Orthodox School and entered the Mor Aphrem theological school at Mosul in 1946 where he completed his education in 1954. He was ordained priest and became a monk in 1947. Later he completed a Masters degree in English at City University of New York and a Master's degree in Pastoral Theology at General Theological Seminary, New York. He was ordained Metropolitan Zakka Mor Severious by Patriarch Yaqub III in 1963. In 1964, Mor Severious discovered the remains of St. Thomas in the sanctuary wall of the church at Mosul. In 1969, Mor Severious became the Metropolitan of Baghdad, where he also served as the Head of Syriac Studies and a member of the educational academy. Mor Severious also served as a member of the World Council of Churches. On September 14, 1980, Mor Severious was consecrated the Patriarch of Antioch by name Ignatius Zakka I, in a rite officiated by Catholicose of the East, Baselious Paulose II along with the archbishops of the Holy Synod.