Kleinmikhel was a soldier.
In 1814, while in France, he saved the Grand Dukes Nicholas and Michael from falling prisoners to Napoleon's troops. In 1816 he became a Colonel, and later a General. In 1831 he played an important part in the suppression of the Polish rebellion. In 1839, after a great fire, he rebuilt the Winter Palace. He then received the title of Count from the Tsar as a sign of gratitude. He adopted the illegitimate children of Nicolas I.
He was closely involved in the development of the railways in Russia (although he was one of the most unpopular officials) and worked closely with George Washington Whistler in the construction of the St Petersburg - Moscow Railroad.
Albert Parry, Whistler's Father, Indianapolis, 1939, pp. 57-62.