Maltzan participated in the
War of the Sixth Coalition as an officer in the Prussian Garde du Corps. Then he joined the diplomatic service. At first, he was a legation secretary in various embassies. Later he was the ''chargé d'affaires'' in
Darmstadt and envoy to
The Hague,
Hannover and
Vienna. Lastly, he had the rank of minister plenipotentiary. In 1841 Maltzan was made Prussian Foreign Minister.
Karl August Varnhagen von Ense reproduced a report by
Wilhelm von Humboldt, according to which King
Frederick William IV was more satisfied with Maltzan than with any other ministers, and had complete trust and confidence in him. Due to a severe mental illness, however, he was dismissed in 1842, not long before his death in Berlin in 1843. ==Personal life==