His inclination for acting had already become obvious in his teenage years when he began organizing and participating in student plays.
After a short stint at a leading theatre school, he moved to Rome where he joined a small group of actors for the purpose of making some documentaries.
Still unsure of his ultimate vocation, he worked various jobs on the crew.
The role as Abel in John Huston's film The Bible (1964) marked a curcial point in his career. After that, Nero got the starring role as Lancelot in Joshua Logan's film Camelot (1967).
At the same time, Nero participated in various spaghetti westerns, such as Django and The Mercenary.
Averaging four film appearances each year, Nero, using Europe as his soundstage, works with directors of the stature of Carlo Lizzani, Damiano Damiani, Luigi Zampa, Luis Bunel, Salvatore Samperi, Elio Petri, Sergei Bondarchuck, Michael Cacoyannis, Rainer Werner Fassbinder, Claude Chabrol, Vatroslav Mimica, and Marco Bellocchio.
Apart from his cinematographic work, Nero also acts on stage. Recently he and his son recorded a song for a charitable organization.