Professor of Constitutional Law at the Aristotle University of Thessaloniki.
Member of the Greek Parliament (1993-2019)
Minister for Press and Mass Media- Government Spokesman (1993-95), Minister for Transport and Communications (1995-96), Minister for Justice (1996), Minister for Culture & Sports (1996 – 1999), Minister for Development, Energy, Industry, Trade, Tourism and Technology (1999-2000), Minister for Culture & Sports 2000-2004 (in charge of coordinating the entire range of aspects of the Athens 2004 Olympic Games preparation (Infrastructures, relations with International Olympic Committee etc.)
Minister for National Defence (2009-2011)
Deputy Prime Minister and Finance Minister (17.06.2011 – 18.03.2012)
President of PASOK (2012-2015 )
Deputy Prime Minister and Minister of Foreign Affairs ( 2013-2015 )
General Rapporteur for the revision of the Greek Constitution ( 1995-2001)
Rapporteur of the Parliamentary Assembly of the Council of Europe for the implementation of the judgments of the European Court of Human Rights ( 2017-2019 ).