Cardinal Karl Lehmann, Bishop emeritus of Mainz, Germany, was born on 16 May 1936 in Sigmaringen, Germany. He was ordained for the Archdiocese of Freiburg im Breisgau on 10 October 1963 and holds doctorates in philosophy and theology from the Pontifical Gregorian University, Rome.
He was an assistant to Fr Karl Rahner at the University of Münster. After earning his "habilitation", he taught dogmatic theology at the Johannes Gutenberg University, Mainz. He was a member of the Central Committee of German Catholics and the Jaeger-Stählin Ecumenical Circle. He later taught at the Albert Ludwig University, Freiburg im Breisgau, and was a member of the International Theological Commission. He also edited the official publication of the documents of the Joint Synod of the Dioceses in the Federal Republic of Germany (Synod of Würzburg, 1971-75).
On 21 June 1983 he was appointed Bishop of Mainz and received episcopal ordination on 2 October.
President of the German Bishops' Conference for 20 years until January 2008 (elected in 1987 and reconfirmed in 1993, in 1999 and in 2005).
In 1991 he was Special Secretary of the First Special Assembly for Europe of the Synod of Bishops.
Since 16 May 2016, Bishop emeritus of Mainz.
He participated in the conclave of April 2005, which elected Pope Benedict XVI and in the conclave of March 2013, which elected Pope Francis.
Created and proclaimed Cardinal by the Bl. John Paul II in the consistory of 21 February 2001, of the Title of S. Leone I (St. Leo I).