Born in Rome, after the diploma in surveying Castelnuovo studied French literature at the university, specializing in Provençal and Troubadour aesthetics.
[1][2] In the same period he started to play guitar and to attend the Folkstudio, a well-known Roman musical club.
[1] Castelnuovo made his record debut with "Oceania", a single which won a selection organized by Domenica in that put up for grabs a place in the 32nd edition of the Sanremo Music Festival.
[1] He entered the competition with the song "Sette fili di canapa", the title track of his debut album, reaching the finals and getting large critical acclaim as well as some commercial success.
[2] According to Enrico Deregibus' Dizionario completo della Canzone Italiana, his songs are "enchanting", especially because of their "fascinating and delicate writing, rich in literary references".