He graduated in double-bass at the Santa Cecilia Conservatory, he studied composition under the tutelage of Armando Renzi and orchestral conductorship with Franco Ferrara and Piero Bellugi. He played the double-bass in the Rai Symphonic Orchestra and started to take part in recording sessions for cinema music. He met the Maestro Nino Rota, and was his assistant from 1975 to 1977, he encouraged him to start his career as a cinema composer. In 1976, Peirsanti composed his first sound track for the debut film by Nanni Moretti I Am Self Sufficient, which was the beginning of an artistic relationship which has lasted over the years: he composed the music for Ecce Bombo (1977), Golden Dreams (1981), Bianca (1983), The Caiman (2006, winning him a David di Donatello, Ciak d'Oro and Ucmf award from the French film composers association, awarded at Cannes) and We Have a Pope (2011). At the beginning of the eighties, the meeting with Gianni Amelio marked another important collaboration. Piersanti composed the soundtracks for Blow to the Heart (1982), I velieri (1983, TV episode for the series Dieci registi italiani, dieci racconti italiani), Open Doors (1989), The Stolen Children (1992, winning him a David di Donatello, Ciak d’oro, and Platea d’oro), Lamerica (1994, another David di Donatello), Così ridevano (1998, Grolla d'Oro), The Keys to the House (2004) and The Missing Star (2006) for him. In the nineties he began working with Mimmo Calopresti, composing the music for The Second Time (1995), Notes of Love (1998), I Prefer the Sound of the Sea (1999) and Happiness Costs Nothing (2002). In addition to the titles cited, during his long career Piersanti has composed more than a hundred sound tracks for the cinema, working with some of the most important filmmakers such as Carlo Lizzani, Ermanno Olmi, Roberto Faenza, Marco Tullio Giordana, Cristina Comencini, Carlo Mazzacurati, Daniele Luchetti, Paolo Virzì, Emanuele Crialese. He has also composed music for the small screen: for example the famous theme tune for the successful TV series Inspector Montalbano, based on the books by Andrea Camilleri. But he has not only worked in cinema and television. He has also composed numerous music for theatrical performances and orchestral and chamber music.