foreign minister of imperial Russia (1822–56) whose policy toward the Ottoman Empire helped precipitate the Crimean War (1853–56).

The son of a German count of the Holy Roman Empire who served as Russia's ambassador to Portugal, Nesselrode entered the Russian navy at the age of 16. When he failed to distinguish himself in the armed forces, he transferred to the diplomatic corps and served in the Russian embassies to Prussia and the Netherlands (1801–06) and as diplomatic secretary to several generals during the war against Napoleonic France (1806–07). After assisting in the conclusion of the Franco-Russian peace of Tilsit (1807), he was attached to the Russian embassy at Paris, where he attempted unsuccessfully to avoid a renewal of war between France and Russia.

After France's defeat Nesselrode attended the Congress of Vienna (Vienna, Congress of) (1814–15), where he urged the Russian emperor Alexander I (reigned 1801–25) to support the restoration of the Bourbons in France. In 1816, despite damage done to his prestige by the discovery of a Franco-Austrian agreement aimed against Russia, Nesselrode was appointed director of the college of foreign affairs and in 1822 assumed full control of the conduct of Russia's foreign affairs.

After the accession of Emperor Nicholas I (1825), Nesselrode tried to maintain the Ottoman Empire as a power dependent on Russia. To this end, he arranged a defensive alliance with the Turks (Treaty of Unkiar Skelessi; 1833) but abandoned it owing to objections by the British, who feared Russian influence in the Mediterranean. Instead, he concluded an Anglo-Russian alliance that led to the Straits Convention of 1841, an international agreement recognizing the Ottoman sultan's right to prevent warships of any nation from passing through the straits leading to the Black Sea. The two powers also agreed to support the Ottoman Empire.

After the outbreak of the Hungarian Revolution of 1848, Nesselrode, who had restrained Nicholas from intervening in the French revolutions of 1830 and 1848, suggested that Russia aid Austria in suppressing it; this act not only crushed the Hungarian rebels but also contributed to the general misconception that Russia was the most powerful nation in Europe. Encouraged by this success, Russia's leaders assumed a more active role in foreign affairs, and, in attempting to curb France's growing influence over the Ottoman Empire, they helped precipitate an international crisis in 1853. Nesselrode, trying to avoid hostilities, prolonged diplomatic negotiations but could not prevent the onset of the Crimean War. At its conclusion he signed the Treaty of Paris (1856), which destroyed the results of his patient efforts to establish Russian preponderance in the Balkan Peninsula. Retiring from the foreign office, he retained only his post as imperial chancellor, which he had held since 1845.