Francesco Marchetti has composed, orchestrated, and conducted film and television scores for more than 30 years, working with Italian and international directors including Fausto Brizzi, Neri Parenti, John Real, Guido and Maurizio De Angelis, and Bruno Zambrini, and on productions such as the TV series Il Commissario Rex.

In 2025, he orchestrated the score for Diamanti, directed by Ferzan Özpetek, whose theme — performed by Giorgia Todrani — received a David di Donatello nomination.

He began composing at 13 and wrote his first opera, Il Conte di Montecristo, at 23; it premiered in 2006 at the Auditorium della Conciliazione in Rome, directed by Jocelyn and later by Gino Landi, who called it "the finest musical ever written in Italy."

Marchetti has conducted the orchestra at the Sanremo Music Festival (2005, 2008) and produced music published in association with Disney, Andrew Lloyd Webber, and an Official Harry Potter publication among others. His theatrical work includes  L'Apocalisse — L'Opera (2012), a digitised opera staged at Rome's Teatro Olimpico featuring Gigi Proietti and Enzo De Caro.

His scores for documentaries addressing major social and contemporary subjects include "Zero" and "The Summit", both directed by Franco Fracassi.

Marchetti also develops software instruments (VST) for music composition; his collaboration with Gary Garritan on an educational tool earned him an Honorary Master's in Film Music from the University of Colorado Springs. In 2023, he composed and orchestrated the official anthem of the International Covid Summit, broadcast live from the European Parliament, Romania, Tokyo, and Washington D.C. In 2000, he arranged the orchestrations for the Jubilee of Youth at Tor Vergata, Rome, performed before Pope John Paul II and an audience of two million.