 He was the Commissioner for Finance and Head of the Budget and Finance Division at the Federal Foreign Office in Berlin.Rücker also held various postings in the Federal Foreign Office in Bonn and German embassies abroad, including Dar es Salaam, Detroit (as Consulate-General) and Vienna.Additionally, he was the Ambassador and Deputy High Representative for Administration and Finance in the Office of the High Representative in Sarajevo, and the Mayor of the city of Sindelfingen in Germany.