[3] He was consecrated a bishop on 7 May 2006[5] by Joachim Meisner, Archbishop of Cologne, with Manfred Melzer and Rainer Maria Woelki as co-consecrators.

He chose as his episcopal motto the Latin phrase Gaudete semper Dominus prope, "Rejoice always, the Lord is near", taken from the Epistle to the Philippians Phil 4:4.

He said: "While we remain committed to the basic right of asylum for refugees from war areas and victims of political persecution, we must ask ourselves what drives such a large number of people on to the streets every Monday and not tar them all with the same brush by a priori labeling them right-wingers.

[7] Following the procedures revived in 1989 following the reunion of Germany, Koch was first elected by the Berlin church and Pope Francis, seeing no objection, made the appointment.

He said "It would have been better to limit the number of topics up for discussion"[10] and "We must not give the impression that the synod spent most of its time quarreling about the conditions for admission to the sacraments.

[12][a] He told the Synod that theological arguments against allowing Catholics in irregular marriages to receive Communion "do not silence the questions in the hearts of people".

Human hostility and stranger hatred are not only in clear contradiction to the values of our free-democratic constitution, but ultimately bear witness to a deep disregard for the Christian message.

[17] Koch, though an advocate for reconciliation between the Church and the LGBT community, denounced the German Bundestag's vote to legalize same-sex marriage on 30 June 2017.