Fagioli was born in San Miguel de Tucumán in northern Argentina in 1981. He started out taking piano lessons, showed musical talent, and was sent to the Instituto Superior de Arte at Buenos Aires' Teatro Colón, one of the country's top music schools. He also took vocal music classes there, and several teachers identified him as a true countertenor even though that vocal specialty was not common in Argentina at the time. Fagioli's range covers three octaves, and he excels in both a powerful top register reminiscent of the actual castrati and at the bottom of his range. He scored a breakthrough in 2003 when he won the Bertelsmann Foundation's Neue Stimmen (New Voices) competition in Gütersloh, Germany. Soon he began to find major bookings in operatic countertenor roles such as the athletic leads in Handel's Giulio Cesare and Ariodante, and Gluck's Orfeo ed Euridice. He has been in demand not only from Baroque operatic conducting specialists such as Alessandrini but from mainstream conductors such as Riccardo Muti, under whom he made his debut at the Salzburg Whitsun Festival in 2007. Fagioli has sung the title role of Handel's Giulio Cesare in a variety of opera houses in many countries, and the castrato roles of Handel are among his specialties. However, he has also inclined toward roles originated by the castrato Gaetano Majorano, called Caffarelli -- a rival to the better-known Farinelli -- and Giambattista Velluti (1780-1861), whose career stretched into the Rossini era. Fagioli's repertory stretches as far back as Monteverdi's L'incoronazione di Poppea.
Although Fagioli's public appearances have mostly been in the operatic realm, his recordings have focused on recitals. In 2013, he released Arias for Caffarelli on the Naïve label, and he has since recorded for Dynamic, Deutsche Grammophon, and other labels. In 2020, he was heard as Nerone (Nero) on an Erato recording of Handel's opera Agrippina, with the early music ensemble Il Pomo d'Oro conducted by Maxim Emelyanychev. ~ James Manheim, Rovi