A sympathizer and secret member of the fascist Iron Guard movement, he was also the royal commissioner involved in the 1934 acquittal of Guard leader Corneliu Zelea Codreanu. Petrovicescu was assigned his ministerial position by Codreanu's successor Horia Sima, serving as one of the main Iron Guardists in the conflicted cabinet headed by Ion Antonescu. In this capacity, he helped Sima obtain control of an armed structure, and, taking the party's side during the Legionnaires' rebellion of 1941, helped organize it in combat against Antonescu.