A grain merchant, he amassed considerable wealth, and was rumored at the time to be the wealthiest man in the Balkans.

On 24 October 1808, by Firman of Sultan Mahmud II Moldavian and Wallachian boyars were required to recognize the primacy of Manuk Bey and therefore recognize the rank of Prince in Moldova as a reflection of the status of a member of the government of the Sublime Porte, as Grand dragoman, Deputy minister of foreign affairs and Grand Treasurer.

[1] In late 1808, the highly influential Manuc was advanced by his protector, the Ottoman general Alemdar Mustafa Pasha, to occupy the Moldavian throne, but was prevented from taking the throne by the fall of his protector; he himself had to flee Istanbul to avoid execution.

Settling in Bucharest (after a short period of refuge in Transylvania), Manuc-Bey kept the inn known today as Manuc's Inn; in time, he also acquired estates in Bessarabia, near Hîncești and Reni, and was to remain the main financial backer of Ypsilanti, lending the treasury 160,000 thalers in all.

During the Russo-Turkish War of 1806–1812, he was also a mediator (1809) between the Russian Imperial Army of Mikhail Andreyevich Miloradovich and a rebel Ottoman garrison in Giurgiu.