Pope Pius XII appointed him titular archbishop of Nicomedia and coadjutor bishop of Monreale on 11 February 1951. He succeeded to the metropolitan see of Monreale on 23 August of that year. In 1961 he was named Titular Archbishop of Sardica and appointed Secretary of the Sacred College of Cardinals on 25 October 1961, thus he served as secretary of the 1963 papal conclave. He was a counselor of the Pontifical Preparatory Commission of the Second Vatican Council from 1961 until 1964. He attended the Second Vatican Council. Pope Paul VI appointed him Pro-Prefect of the Congregation for Divine Worship and the Discipline of the Sacraments on 7 April 1967.