Reiner Braun studied German Literature, History and Journalism.
Since 1982 he has been actively involved in the Peace Mouvement, working for many years as Executive Director for Scientist for Peace and Sustainability (Germany) and the International Network of Engineers and Scientists for Global Responsibility (INES).
From 2003 till 2005 Reiner Braun worked for various projects related to the Einstein year 2005 at the Max Planck Institute for the History of Science in Berlin and for the Max Planck Society.
Since 2006 he is the Executive Director of German IALANA Germany, the international Ialana since 2012 He was Executuve Director of the Vereinigung Deutscher Wissenschaftler (VDW), the German pugwash group from 2006 till 2013.
Since september 2013 He is Co-president of the International Peace Bureau (IPB) and one of the speaker of the German peace mouvement.