In 1855, Walewski succeeded Drouyn de Lhuys as Minister of Foreign Affairs and he acted as French plenipotentiary at the Congress of Paris the following year. As foreign minister, Walewski advocated "entente" with Russia, opposing his emperor's adventurous strategy in Italy which led to war with Austria in 1859. After leaving the Foreign Ministry in 1860 he became France's Minister of State, an office which he held until 1863. He served as senator from 1855 to 1865, before being appointed to the "Corps Législatif" in 1865 and as president of the Chamber of Deputies by the Emperor, who returned him to the Senate after a revolt against his authority two years later.