|Reference style||His Eminence|
|Spoken style||Your Eminence|
Born in Lille to a bourgeois family of cloth merchants, Liénart was the second of the four children of Achille Philippe Hyacinthe Liénart and Louise Delesalle. He studied at College Saint-Joseph, the Seminary of Saint-Sulpice in Paris, the Institut Catholique de Paris, Collège de Sorbonne, and the Pontifical Biblical Institute in Rome. He was ordained to the priesthood on 29 June 1907, and then taught at the Seminary of Cambrai until 1910, and then at Lille until 1914. During World War I Liénart served as a chaplain to the French Army, and did pastoral work in his hometown from 1919 to 1928. As a priest, he championed social reform, trade unionism, and the Worker Priest movement.
On 6 October 1928 he was appointed Bishop of Lille by Pope Pius XI. Liénart received his episcopal consecration on the following December 8 from Bishop Charles-Albert-Joseph Lecomte of Amiens, with Bishops Palmyre Jasoone and Maurice Feltin serving as co-consecrators, in Tourcoing. He was created Cardinal Priest of S. Sisto by Pius XI in the consistory of 30 June 1930. By coincidence, one of the first priests he ordained, on 21 September 1929, was a certain Marcel Lefebvre. Liénart's and Lefebvre's paths would be interwined during the following years, even serving both on the Central Preparatory Commission for the Second Vatican Council. And it was Liénart who, as Cardinal, in 1947 would consecrate Lefebvre (who had been appointed as Apostolic Vicar of Dakar in Senegal), to the Episcopate.
Liénart, who participated in the 1939 papal conclave, was elected President of the French Episcopal Conference in 1948, representing the Catholic Church in France, and remained in that post until 1964. An elector in the 1958 papal conclave, he was named the first Territorial Prelate of Mission de France on 13 November 1954 and later resigned from this post in 1964.
An active participant of the Second Vatican Council (1962–1965), Liénart was a leading liberal voice at the Council and sat on its Board of Presidency. When the Roman Curia, composed predominantly of conservative prelates, issued a list of nominees for the members of the Council's commissions, Liénart objected that nothing of the nominees' qualifications were included. Liénart, assisted by Cardinals Bernardus Johannes Alfrink and Giovanni Colombo, delivered one of the closing messages of the Council on 8 December 1965. He was also one of the cardinal electors in the 1963 papal conclave, which selected Pope Paul VI.
Liénart resigned as Lille's bishop on 14 March 1968, after forty years of service. He lost, on January 1, 1971, the right to participate in a conclave, having already reached age 80. After his death at age 89, he was buried in the Cathédrale Notre-Dame-de-la-Treille.
- Time Magazine. Recent Deaths February 26, 1973
- Ordained priest at Lille, France, by Msgr Achille Liénart, Bishop of Lille, on 21 September 1929 Archbishop Marcel Lefebvre - Useful Information Archived 2004-07-03 at the Wayback Machine. Society of Saint Pius X, District of Great Britain
- Leaders of the Church During the Vichy Regime. Cardinal Achille Lienart Archived February 20, 2007, at the Wayback Machine.
- Time Magazine. The Council Opens 19 October 1962
- Lefebvre, Marcel. "They Have Uncrowned Him". 4th ed. Kansas City: Angelus Press, 1988.
- Christus Rex. To Rulers
|Catholic Church titles|
| Bishop of Lille
Emmanuel Célestin Suhard
| President of the French Episcopal Conference