[2] A staunch supporter of the National Fascist Party from its early days, Barberini was an active squadrista and began his career in the Milizia Volontaria per la Sicurezza Nazionale (MVSN) in 1923.

He participated in major MVSN expeditions, including those in Spain and Libya, where he commanded the II Legion, and in East Africa, where he distinguished himself in 1937 among the officers suppressing Ethiopian guerrillas.

[2][3] He served on the national council and directorate that Mussolini had established alongside Secretary Aldo Vidussoni, which included Ferdinando Mezzasoma, Augusto Venturi, Mario Farnesi, and Carlo Ravasio.

Beginning on 2 March, he coordinated extensive raids in the southern territories of the province, leading nine companies from Grosseto, Siena, Orvieto, and Viterbo to intimidate the population and encourage enlistment in the RSI.

The Assize Court of Grosseto charged him with murder, collaboration with the Nazis, theft, and embezzlement, particularly in relation to the Maiano Lavacchio massacre, where eleven draft evaders were killed by the 98th Legion.