He gained distinction in the Seven Years' War and the conquest of Crimea. Prozorovsky's career was furthered by his maternal Galitzine relatives, who helped him to get appointed to the office of Kursk's governor in 1780. He resigned two years later and spent the following years at his country estates.
In 1790 he returned to the active service as the Governor General of Moscow. Emperor Paul, however, couldn't get along with him and discharged Prozorovsky from his office. His ancient services were recalled in 1808, when the Russian army resumed its hostilities against Turkey, and Prozorovsky became its Commander-in-Chief.
His reputation suffered a blow when his storm of Brăila ended in his army being repelled at enormous loss of life on Russian side. The old and ailing general asked Alexander I to dispatch a younger and more energetic Mikhail Kutuzov to his aid.