Born and raised in Gelsenkirchen, Kretschmann completed his secondary education at the Max Planck Gymnasium.
After studying business administration in Aachen, Bochum and Dortmund, he was awarded a doctoral degree in Economics (Dr. rer.
From 1990 to 2001, Kretschmann held various management positions at Ruhrkohle AG, most recently as personal advisor to the Deputy Chairman of the Executive Board and Labour Director of the RAG.
Since 2006, he is chairperson of the management board of DMT-Gesellschaft für Lehre und Bildung GmbH and president of the Technische Hochschule Georg Agricola University in Bochum.
Kretschmann is a member of numerous national and international professional bodies, currently (2018/19) President of the Society of Mining Professors – Societät der Bergbaukunde.