Decourtray received on 29 June 1947, the sacrament of Holy Orders, and celebrated his first Mass in July 1947 in Seclin, where he lived with his family since 1938. His motto was Simplicitate (Latin for " in simplicity "). He became a priest in the diocese of Lille. From 1948 to 1951 he completed his doctoral studies at the Pontifical Gregorian University, which he did. Having the academic degree of a Doctor of Divinity completed. During this period of study in Rome, he was also chaplain to the Church of St. Louis of the French. Subsequently, he was from 1952 professor at the seminary of Lille, from 1965, vicar general in the same diocese and from 1966 Archdeacon of Roubaix.
Pope Paul VI. appointed him on 27 May 1971 as Titular Bishop of Hippo Diarrhytus and auxiliary bishop in Dijon. The episcopal ordination he received on 3 July of the same year by Bishop Adrien Gand. Co-consecrators were the bishops André de la Brousse and Jean Sauvage. On April 22, 1974, he was appointed bishop of Dijon. On October 29, 1981, Pope John Paul II appointed Archbishop of Lyon, and thus Primate of France. In addition, he gave him on 23 April 1982 the Office of the prelates of the Territorialprälatur Mission de France o Pontigny and took him on 25 May 1985 as a cardinal priest with the titular church of Santissima Trinità al Monte Pincio in the College of Cardinals to. From 1987 to 1990 he was also President of the French Episcopal Conference and a member of the Pontifical Council for Interreligious Dialogue and dialogue with non-believers. In 1988 he resigned from the office of Prelate of the Prelature of " Mission de France ".
Cardinal Decourtray was elected on 1 July 1993 as a member of the Académie française, which he succeeded Professor Hamburger on seat 4. His official appointment was on 10 March 1994. Decourtray Albert died on 16 September 1994 in Lyon and was buried on 22 September of the same year in the crypt of the Cathedral of Lyon. After his death, the Archbishop of Paris, Jean -Marie Cardinal Lustiger was his successor as a member of the Académie Française.