Cardinal Johannes Willebrands, President emeritus of the Pontifical Council for the Promotion of Christian Unity, was born on 4 September 1909 in Bovenkarspel, diocese of Haarlem (the Netherlands). He was ordained priest on 26 May 1934.

After having studied in Rome, he returned to Holland in 1937 and acted as chaplain of the Church of Begijnhof in Amsterdam and in 1940 he taught philosophy at the major seminary in Warmond. Five years later he became rector. He demonstrated a very active interest in the cause of Christian unity as president of the St. Willibrord Association which promoted ecumenicism in Holland and in 1951 organized a Catholic Conference on ecumenical questions. On 24 June 1960 Pope John XXIII nominated him Secretary of the newly established Secretariat for the Union of Christians. During the work of the second Vatican Council he prepared the documents relevant to ecumenism, religious liberty and relations with non-Christian religions.

He was nominated titular Bishop of Mauriana in 4 June 1964 and received episcopal ordination on 28 June 1964 by Pope Paul VI. 

On 12 April 1969 Pope Paul VI named him President of the Secretariat for the Union of Christians.

On 6 December 1975 he was promoted to Archbishop of Utrecht and primate of Holland, continuing at the same time as President of the Secretariat for the Union of Christians. On 3 December 1983 he resigned as Archbishop of Utrecht.

Acted as first Presidente Delegate at the Special Synod of Dutch Bishops, 14-31 January 1980. Acted as President Delegate at the II Extraordinary Assembly of World Synod of Bishops, 24 November - 8 December 1985.

On 12 December 1989, President emeritus of the Pontifical Council for the Promotion of Christian Unity.

Created and proclaimed Cardinal by Paul VI in the Consistory of 28 April 1969, of the Title of S. Sebastiano alle Catacombe (St. Sebastian at the Catacombs). 

Cardinal Johannes Willebrands died on 2 August 2006.