In 1750, he was made Hetman of the Ukrainian Cossacks. He served as hetman until 1764. Selecting Hlukhiv and Baturyn as places of hetman's residence, Razumovsky had opulent baroque palaces erected in these sleepy towns by the imperial architect Andrey Kvasov. He also planned to open a Ukrainian university in Baturyn.
Catherine the Great, whom he wholeheartedly supported during the reign of her husband, made him a Field-Marshal, although he never saw a battle. She was soon disappointed, however, by his management of Ukraine. She didn't like his idea to make hetmanship a hereditary office, either, and abolished it altogether.