Carlo Guelfi was born in Rome and studied singing with his uncle Renato Guelfi. In 1983 he won the International Competition "Aureliano Pertile". From that point on he embarked on a brilliant career collaborating with the most important opera houses and musical institutions in the world.
These included the Teatro alla Scala (La Gioconda, Tosca and Adriana Lecouvreur) and the Teatro dell'Opera in Rome (Il Principe felice and Aida). Others were the Teatro Comunale in Florence (Un Ballo in maschera, La Fanciulla del west, Aida, La Traviata, Cavalleria rusticana and Pagliacci) and the Teatro Comunale of Bologna (Otello). In addition there were the Teatro Carlo Felice in Genova (La Giocanda, Macbeth and Andrea Chénier) and the Teatro La Fenice in Venice (Rigoletto, Aida, Maria di Rohan, Samson et Dalila and Simon Boccanegra). There were also the Arena di Verona (Rigoletto, Aida and La Traviata), the Accademia di Santa Cecilia (Carmina Burana) and the Carnegie Hall in New York (I Puritani, Giovanna d'Arco and Ernani). Others included the Staatsoper in Vienna (Il Trovatore and Macbeth), in Tokyo while on tour with the Teatro Comunale of Bologna (Cavalleria rusticana) and in Tokyo while on tour with the Teatro Comunale of Florence (Aida). Furthermore, there were the New National Foundation of Tokyo (Un Ballo in maschera) and the Opernhaus of Zurich (La Fanciulla del west, Carmen, Rigoletto and Sly). Others were the Staatsoper in Munich (Il Trovatore), the Salzburg Festival (Simon Boccanegra, the Metropolitan in New York (Rigoletto) and the Teatro Real in Madrid (Il Trovatore).
In 2001 he inaugurated the season at the Teatro La Fenice in Venice with Simon Boccanegra and made his debut in Andrea Chénier at the Teatro Carlo Felice in Genova with orchestral conductor Michel Plasson. He sang in La Traviata conducted by Zubin Mehta while on tour with the Teatro Comunale of Florence in Tokyo and inaugurated the Maggio Musicale Fiorentino in Florence with Il Trovatore conducted by Zubin Mehta. He performed in Aida conducted by Daniele Gatti at the Teatro Comunale in Bologna (June) and was in Aida and Rigoletto at the Festival d'Orange. He sang in La Traviata and Aida in the Arena di Verona and made his debut in Attila in the Opéra Bastille in Paris (September-October 2001) and at the Teatro Comunale in Florence. He also performed in La Battaglia di Legnano at the Carnegie Hall in New York.
Carlo Guelfi's future engagements include the inauguration of the Teatro dell'Opera in Rome with Gianni Schicchi and Il Tabarro (January-February 2002), Rigoletto and Tosca at the Metropolitan in New York (March-April 2002), Tosca in Tokyo (April-May 2002) and Simon Boccanegra, conducted by Claudio Abbado (June 2002).
He has worked with the most important orchestra conductors including Claudio Abbado, Bruno Bartroletti, Leonard Bernstein, Semyon Bychkov, Daniele Gatti and Gianluigi Gelmetti. Others are Carlo Maria Giulini, Peter Maag, Zubin Mehta, Antonio Pappano and Christian Thielemann.