From 1743 to 1744, Kirill Razumovsky incognito attended the University of Göttingen. Razumovsky's adjutant in his journey to Germany was Grigory Teplov. Teplov wielded influence over Little Russia in his capacity as the secretary and advisor to Kirill Razumovsky (whose cousin he married). Razumovsky was appointed President of the Russian Academy of Sciences when he just turned 18 years old due to the influence of his brother, Aleksey Razumovsky, the morganatic husband of Empress Elisabeth of Russia.
In 1750, Razumovsky was elected and subsequently appointed Hetman of Zaporizhian Host, a title he held until Catherine II of Russia abolished this title in 1764, in exchange Razumovsky was granted a rank of Field marshal of Russian Army in 1764. During his service as Hetman of Zaporizhian Host, Baturin was re-established as residence of the Hetman, and Razumovsky had opulent baroque palaces erected both in Baturyn as well as in Glukhov by the imperial architect Andrey Kvasov and Charles Cameron. Together with Grigory Teplov he also planned to open a university in Baturyn. Kirill Razumovsky died in January 1803 in Baturyn, where he was interred according to his wishes without any pomp, in stark contrast to his rather flamboyant lifestyle.
Kirill married Yekaterina Naryshkina and had five sons, of whom Count Aleksey Kirillovich Razumovsky (1748–1822) was the Minister of Education in 1810–1816, and Prince Andrey Razumovsky (1752–1836) was the Russian plenipotentiary ambassador in Vienna in the years of the Congress 1814–1815. However, Andrey has become better known for his role as patron of Ludwig van Beethoven who dedicated three String Quartets, Op.59 1, 2 and 3, as well as the 5th and 6th Symphonies to him. Any living descendants in the male line of Kirill Razumovsky arise from the progeniture of his fourth son Gregory Razumovsky (1759–1837), who had to emigrate to Western Europe and acquired relative fame as natural scientist and member of a number of distinguished scientific societies in Austria, Prussia and Switzerland.