He graduated from the Rossini Conservatory at Pesaro, where he first met and sang with Renata Tebaldi, with whom he would form something of an operatic dream team of the 1950s.
His early mentors as a singer included Arturo Melocchi, his teacher at Pesaro, and Cherubino Raffaelli, who recognized his talent and helped launch his career.
Del Monaco sang at the New York Metropolitan Opera from 1951 to 1959, enjoying particular success in dramatic Verdi parts such as Radamès.
He soon established himself as one of four Italian tenor superstars who reached the peak of their fame in the 1950s and '60s, the others being Giuseppe Di Stefano, Carlo Bergonzi and Franco Corelli.
However, the book published by Elisabetta Romagnolo, Mario Del Monaco, Monumentum aere perennius, Azzali 2002, lists only 218 appearances by him as Otello, which is a more realistic figure.
[3] The soprano Magda Olivero noted in an interview with Stefan Zucker that: When Del Monaco and I sang Francesca da Rimini together at La Scala [in 1959] he explained his whole vocal technique to me.
When he finished I said, "My dear Del Monaco, if I had to put into practice all the things you’ve told me, I’d stop singing right away and just disappear."