[2] After studying law at the University of Munich, and later in the United States at Columbia, Stanford and Yale universities, Dohnanyi started his career with the Max Planck Institute for International Private Law.

In 1981, Dohnanyi was elected First Mayor of his home city, and thus Minister-President of Hamburg, one of the federal States of Germany.

[2] After the fall of the Berlin Wall and with German unification, Dohnanyi became involved with the restructuring programme in East Germany, and from 1993 to 1996 was a special adviser on Market Economy and State to the Board of the Treuhandanstalt and BvS, its successor company, responsible for privatising state-owned companies in the former East Germany.

[2] Dohnanyi is a member of the Konvent für Deutschland [de], a cross-party think-tank of conservative-liberal orientation.

[4] In 2004, Dohnanyi co-chaired (alongside Edgar Most) a government-appointed commission which presented Minister Manfred Stolpe, then serving as cabinet minister charged with eastern reconstruction, with a 29-page report ("Recommendations for a Change in Direction for Development East").