Hans-Dieter Hermann began his medical studies in Antwerp (Belgium) and eventually switched to psychology. He graduated from the University of Würzburg in 1988. Subsequently, he worked as a scientific assistant to Professor Hans Eberspächer at the Institute for Sports and Sports Sciences, University of Heidelberg. During this time he also worked as an associated psychologist at the Olympic Training Center Rhein-Neckar and its integrated medical therapy and training center.
Since the 1990s, Hans-Dieter Hermann has been working together with many individual athletes and national teams (boxing, gymnastics and field hockey) of the German sports federation (DSB, later DOSB) as part of preparations for international championships and Olympic Games, continuing the path of his mentor Hans Eberspächer. Furthermore, he worked with various professional club teams (e.g. TSG 1899 Hoffenheim) as well as the Austrian national ski team and the Swiss judo national team. In 2004, Jürgen Klinsmann appointed him to the German men’s national football team staff. Since then he has been involved in all core activities, international competitions and international tournaments. He has also worked as a TV expert for the German public television channel ZDF in the course of its broadcast of the 2012 Olympic Games in London and Sochi 2014.
Since 1993, Hans-Dieter Hermann has been working as a management coach and lecturer at various business enterprises and groups. Together with his long-term business partner Professor Jan Mayer, he is the managing director and co-owner of a consulting institute founded in 2007 (Coaching Competence Cooperation Rhein-Neckar).
Hans-Dieter Hermann has been teaching as a professor at the German University for Prevention and Health Management in Saarbrücken since 2010 and held a guest professorship at the Institute for Sports Science of the University of Saarland from 2013 to 2016. In 2010 he was awarded a prize from the German Psychological Society (DGPs) for his contributions to the reputation of psychology in the public. Hans-Dieter Hermann was appointed as honorary professor for "Applied Sports Psychology" at the Institute for Sports Science of the University of Tübingen in the summer semester 2017.