Genn was born on 6 March 1950 in the municipality of Burgbrohl, which is located in the Ahrweiler district of the German state of Rhineland-Palatinate.

[4] Upon being made a priest, he was appointed a curate of the Holy Cross Church in Bad Kreuznach, a position he held for two years.

[4] On 4 April 2003, he was then transferred by Pope John Paul II with his appointment as the third Bishop of Essen.

[2] Genn was appointed the seventy-sixth Bishop of Münster on 19 December 2008 by Pope Benedict XVI after being elected by the cathedral chapter,[3] succeeding Reinhard Lettmann.

Moreover, the eagle relates to his Latin episcopal motto, Annuntiamus vobis vitam, which is taken from 1 John 1, 1–4.

He supported a document "Leben in gelingenden Beziehungen - Grundlinien einer erneuerten Sexualethik", in which a reform of Rom-catholic sexual ethic is part of the text, for example for same-sex partnerships.