With nothing like Tito Gobbi's incisive voice and cunning histrionic ability, Giuseppe Taddei's sumptuous sound and witty personality, or Ettore Bastianini's bronzed vocal instrument, Aldo Protti nonetheless managed a significant career in the Italy of the 1950s and 1960s. Essentially a house baritone for London/Decca Records before the company acquired Bastianini, Protti performed leading roles in Aida, Rigoletto, La Traviata, I Pagliacci, Cavalleria Rusticana, and Otello. While lacking a glamorous presence and sound, Protti was reliable, often more than that.
At the end of WWII, Protti entered the Conservatorio Musicale di Parma and, in 1948, won first prize in Bologna's Concorso Nazionale di Canto. His debut took place on October 9, 1948, at the Teatro Pergolesi di Jesi as Rossini's Figaro. Less than two years later, Protti was at La Scala singing Amonasro in Aida. From that point forward, Protti sang in many of Italy's leading theaters as well as making guest appearances in Vienna. Beginning in 1955, Protti participated in broadcasts on Televisione Italiana, also becoming a frequent guest in productions broadcast on Italian radio. For the latter, he reached beyond Verdi to include such rarities as La Morte di Danton (Danton's Tod) and Genoveva. He also appeared in a broadcast of Lorenzo Perosi's La passione di Cristo. In 1957, Protti appeared with the Lyric Opera of Chicago as Barnaba and Marcello, but, with Gobbi, MacNeil, and Bastianini already on the roster, the company had no further need of his services.
When Herbert von Karajan recorded Otello in 1961, Bastianini was the Iago of choice. When it became clear that Bastianini had failed to learn the part, however, Karajan insisted on Protti (by then, Vienna's resident Iago) for the role. While Decca officials had serious reservations, Protti rose to create a performance leagues ahead of his 1954 recording for the company.
Much decorated, Protti was the recipient of such honors as the Viotti d'Oro in 1961, the Gazzotti d'Oro in 1963, and, in 1969, a nomination as a Cavaliere della Repubblica Italiana. Among his roles, Rigoletto was the one he performed most often, a remarkable 425 times in all; Scarpia, di Luna, Don Carlo, and Iago each figured more than 100 times on Protti's performance roster.