[1] He studied legal science in Göttingen and Berlin, following which he joined the Prussian civil service.

However, differences between the two states came more to the fore under Austrian prime minister Prince Felix zu Schwarzenberg, and Bernstorff's opposition to the Prince's German policy brought about his recall from his post at the express wishes of the Austrian side in 1851.

Shortly before the outbreak of the Crimean War in 1854, he was sent as head of the Prussian embassy in London, and was successful in promoting good Anglo-Prussian relations.

(He had previously been offered the position of Foreign Minister in 1848 and 1850 by King Frederick William IV without taking it up.)

Bernstorff revived a project from 1849 to form a narrow Prusso-German Bundestaat in order to ward off such initiatives by Austria, and argued for a "Lesser German" union under Prussian leadership and excluding Austria; these plans were not pursued for the time being, however, as they were undermined by mistrust of political elements.

Bernstorff also negotiated military conventions with various northern German states, concluded a free-trade agreement with France as part of changes to the Zollverein policy to isolate protectionist Austria, and swiftly recognized the new Kingdom of Italy as a state in hopes that it would help collaborate against Austria.

[2] During this time, he also served as the Prussian delegate at the London Peace Conference of 1864, which led to the signing of the Treaty of Vienna.

[4] In 1867, he was also the ambassador of the North German Confederation at the negotiations for the Treaty of London, which determined the status of Luxembourg.