After studying law and political sciences in Bonn, Geneva, and Harvard he joined the German Foreign Office in 1975. In 1998–2001 he was Deputy Foreign Minister in the Foreign Office; in 2001–06 German Ambassador to the USA; in 2006–08 German Ambassador in London. In 1995–98 he led the German delegation in Dayton, Ohio during the Bosnia peace talks in the Kosovo crisis, and in negotiations concerning the NATO-Russia Founding Act. In 2007 he was the EU Representative in the Troika negotiations on the status of Kosovo. In 2012 he was appointed by President Hollande to the commission drafting the French White Paper on Defence and National Security, and in spring 2014 he represented the OSCE in efforts to create a national dialogue in Ukraine. Since December 2014 he has chaired the OSCE panel of “Eminent Persons.” He is Honorary Professor at the University of Tübingen, and in 2015 became Senior Professor at the Hertie School of Governance. He has been awarded the Order of Merit of the Federal Republic of Germany, alongside numerous foreign orders and distinctions.