Thomas Maissen was born in 1962 in Zurich. From 1981 to 1989 he studied history, Latin and philosophy at the University of Basel, in Rome, and in Geneva. He did his PhD on Italian Authors of the 15th and 16th Centuries Writing on the French History in Basel in 1993 under professor Hans Rudolf Guggisberg. He was an expert collaborator of the University of Potsdam from 1993 to 1995, a collaborator of the Neue Zürcher Zeitung responsible for historical analyses from 1996 to 2004, and was habilitated in 2002 at the University of Zurich. He was a professor at the University of Lucerne from 2002 to 2004.
Since the winter semester 2004/05, he has been teaching modern history at the University of Heidelberg. He has been member of the Heidelberg Academy of Sciences since 2007. In 2009, he was visiting professor at the EHESS in Paris, in 2010 Visiting Fellow at the Institute for Advanced Study in Princeton. His research focuses on the history of historiography, the history of the political thought, the history of mentality, historical images, the history of Switzerland as well as the history of education and school systems. He has been the head of the German Historical Institute Paris (DHIP) since September 2013.