He is a training and teaching psychoanalyst in the German Psychoanalytic Association (DPG) and in the German Association for Group Psychotherapy and Group Dynamics (DAGG), and he has additional training in Ericksonian hypnotherapy, Gestalt, body and music therapy and holotropic breathing (Grof).
Dr. Mahr has been practicing and developing systemic constellation work (SCW) since 1990 and is the President of the Institute for Systemic Constellations and Integral Solutions in Wuerzburg (ISAIL), Germany. Between 2002 - 2004, he was president of the international Germany-based constellations association (IAG). He is a founding member of the International Systemic Constellations Association (ISCA). Dr. Mahr is an international teacher of SCW and founder (2002) of the International Political Constellations Association (IPCA).
Since 2001, together with his wife Brigitta, Dr. Mahr is the organising large international conferences in the series “Fields of Conflict – Fields of Wisdom. Resolutions in Large Group Conflict”, including both the well known and the cutting edge approaches of conflict transformation in addition to constellation work. Among others, the themes of the conferences have been “Collective Wisdom” or “Identities”, and the 2011 conference is dedicated to the issue of conflict transformation and trans-religious spirituality. He is also a founding member of Friendship Across Borders (FAB), presided by Brigitta Mahr. FAB runs a trialogue training and educational program for Israeli, Palestinian and German young adults to become 'peace carriers', offering systemic constellations work in the training process.
In 2010 Dr. Mahr has also initiated a pilot project on the
application of systemic constellation work for members of the European Union.
Currently Dr. Mahr is involved in a pilot project in Rwanda, researching the possibilities of supporting and healing post-traumatic societies through constellation work.
In addition to a number of articles in the German journal “Praxis der Systemaufstellung” ("The Practice of Systemic Constellations") and in the international constellation journal “The Knowing Field”, Dr. Mahr has edited the book “Fields of Conflict – Fields of Wisdom. Systemic Constellations in Peace and Reconciliation Work” (Germany, 2003).