 Also through his mother, hailing from the Cernovodeanu clan, the future diplomat belonged to the boyar nobility, and was an uncle of the historian Dan Cernovodeanu.His collaborator and subordinate Noti Constantinide further argues that Petrescu was of Romany descent, "a true, purebred, Gypsy" and "highly unusual character".Having studied at the University of Bucharest and the University of Paris, he took a doctorate in Law and Political Science at the latter, and began his career as an Ilfov County judge in 1906.