Cardinal Koch was born on March 15, 1950 in Emmenbrücke.
He was ordained a Priest on Jun3 20, 1982 for Basel, Switzerland, and on August 21, 1995 was selected as Bishop for that diocese. He was confirmed as the Bishop of Basel on December 6, 1995 and ordained on January 6, 1996.
On July 1, 2010 he was appointed Archbishop, as a Personal Title, and President of the Pontifical Council for Promoting Christian Unity, a position that he ceased upon the retirement of Pope Bendict XVI on February 28, 2013.
He was elevated to Cardinal November 20, 2010 and appointed Cardinal-Deacon of Nostra Signora del Sacro Cuore. He was installed on January 1, 2011.