Pietro was born in Caserta in 1976 and attended the Accademy of fine arts, where he studied painting. Self-taught, he was a teacher in a prison in Naples, he worked as the organiser and planner of the Cinedamm film season between 1998 and 2003 at the Damm in Montesanto, Naples. Meanwhile he started to make radio (Il tempo dei magliari) and video documentaries (Carta, Scampia, Il cantiere, La baracca).
In 2007 he realized the documentary Il Passaggio della Linea (Crossing the Line), presented at the Venice International Film Festival, which revealed him internationally as author.
In 2009 he has directed the award-winning film La bocca del lupo (The Mouth of the wolf) (Best movie and Fipresci award at the 27th Turin Film Festival, the Prix International de la Scam at the Festival Cinéma du Réel in Paris, the Caligari Preis at the Berlinale and the International Jury Prize and Signis Prize at BAFICI and many others).