He was the oldest surviving child of Friedrich Leopold Graf zu Eulenburg (Prassen, 26 December 1787 - Königsberg, 30 July 1845) and Amalie Julie Eleonore née von Kleist (Perkuiken, 26 May 1792 - Königsberg, 16 November 1830).

Eulenburg studied law at the Universities of Königsberg and Bonn[1] and worked as a government official in Oppeln then in various ministries in Berlin.

On 24 January 1861, he concluded a Japanese-Prussian Treaty of Amity and Commerce with Muragaki Norimasa of the Tokugawa shogunate in Edo period, which was based on Anglo-Japanese Treaty of Amity and Commerce.

He accompanied King Wilhelm I of Prussia in the negotiations with the French ambassador Count Benedetti at Bad Ems prior to the Franco-Prussian War.

[1] His plan to reform the municipal administration in Prussia was opposed by Otto von Bismarck and Eulenburg resigned on 30 November 1878 to be succeeded by his first cousin once removed Botho zu Eulenburg.