Mayer was born in Altötting, Germany, one of three children of Royal Bavarian General Ludwig Mayer and his wife Meta Hoeness. He was the nephew of Württemberg President Eugen Bolz.
He was ordained a Priest on 25 August 1935. After his ordination he was a faculty member at the abbey of Saint Michael from 1937 until 1939. He taught at the Pontifical Roman Athenaeum of Sant Anselmo from 1939 until 1966, serving as its rector from 1949 until 1966. As rector he founded the Pontifical Liturgical Institute.[1]
He was the Apostolic visitor to the Swiss seminaries from 1957 until 1959. He served as Secretary of the Preparatory Commission of the Second Vatican Council from 1960 until 1962. The decree he oversaw on the formation of priests was the only Council document to be approved by the Council Fathers in the first reading. He was elected abbot of St. Michael's Abbey, Metten, Bavaria on 3 November 1966.[1] He received the abbatial blessing from Rudolf Graber, bishop of Regensburg. In 1968 became the abbot-president of the Bavarian Benedictine Congregation, and in 1970 president of the Salzburg Conference of Abbots, positions he held until 1971.
He was created and proclaimed Cardinal-Deacon of Sant'Anselmo all'Aventino in the consistory of 25 May 1985. He was named full Prefect of the Congregation two days later. He presided over the unification of two distinct congregations, the Congregation of the Sacraments and the Congregation for Divine Worship that were united under one name from 1988 on. He resigned the prefecture on 1 July 1988. He was appointed the first President of the Pontifical Commission Ecclesia Dei the next day.[2] He lost the right to participate in a conclave when turned 80 years of age in 1991. He resigned the presidency on 1 July 1991. He opted for the order of cardinal priests and his deaconry was elevated pro hac vice to title on 29 January 1996.[4]
Mayer was the oldest living Cardinal from 2007 to his death. He died on 30 April 2010 in Rome. He was buried at St. Michael's Abbey, Metten.
In 2009, the Saint Benedict Education Foundation announced the establishment of the Paul Augustin Cardinal Mayer, O.S.B., Chair in Sacramental Theology at Sant Anselmo.[5]