Cantacuzino's involvement with the Wallachian administration began during the late stages of the Phanariote era, when both Principalities were being Hellenized. He first became a titled boyar in 1813, under Prince John Caradja, when he was appointed "Serdar" of the Wallachian military forces; in 1820, he was an "Aga", or head of Wallachia's police. In 1821, following the Greek War of Independence and the anti-Phanariote uprising, he and his family took refuge in the Austrian Empire, joining a colony of boyars in Corona (Brașov). An anonymous letter, tentatively dated to April 1821, cites him as one of the boyars attracted into the anti-Phanariote faction of this diaspora, alongside Grigore Brâncoveanu, Scarlat Rosetti and Alexandru Vilara.