 In 1875, he became acting Ambassador to St. Petersburg, where he offered Russia German support for Russian interests in the Balkans in exchange for Russian support for German interests in Western Europe.In 1878 he took part at the Congress of Berlin.After the death of Bernhard Ernst von Bülow, Radowitz was appointed as acting Foreign Secretary, until he was succeeded by Chlodwig, Prince of Hohenlohe-Schillingsfürst.