After the war, he sang at the Teatro Verdi in Florence in 1919 and then the Teatro Costanzi in Rome where he sang leading roles in Verdi's La Forza del Destino, Ponchielli's La Gioconda, Rossini's Il barbière di Siviglia, and Aida. He made his Teatro alla Scala debut in 1921 as Pogner in Wagner's Die Meistersinger. This and other German roles in Tristan und Isolde and Salome were sung in Italian translations. He sang Tagellino in the premiere of Boito's Nerone in 1924. During this time, he also sang in Naples, Turin, and other Italian opera houses.
His Metropolitan Opera debut came in 1926 as Pontifex Maximus in Spontini's La Vestale. He sang there for the next 22 years, and was greatly admired for his interpretations of leading Verdi roles in La Forza del Destino, Simon Boccanegra, Aida, and Rigoletto. Even more important was his participation in the revivals of Mozart's Don Giovanni and Le nozze di Figaro; his importance to the success of these productions cannot be overestimated, with his good looks having as much to do with his fame as his superb vocal abilities. Pinza was equally popular in several French operas including Gounod's Faust, Delibes' Lakme, and Bizet's Carmen. His Russian roles included King Didon in Rimsky-Korsakov's Le Coq d'Or (in French) and Boris Godunov (in Italian). Other important roles at the Metropolian Opera were Raimondo in Lucia di Lammermoor, Basilio in Il barbière di Siviglia and the Father in Louise.
Pinza also appeared regularly in Europe at Covent Garden, the Paris Opera, Salzburg Festival, Florence, and Vienna State Opera. He appeared every season at the Teatro Colon in Buenos Aires from 1925 until 1932. In the United States, he also sang in Chicago and San Francisco. Late in his career, he appeared with his daughter, Claudia Pinza, who had a minor career singing leading soprano roles. After his retirement from the opera stage, he made a successful Broadway debut in South Pacific and later in Fanny. He also appeared in several motion pictures.
His voice was a rich basso cantante and had an easy elegance of phrasing, which is exhibited in nearly all of his recordings. He was at a disadvantage from some of his colleagues because he could not read music, but this meant that he was more willing to follow the concept of the conductor and, indeed, he was a favorite of Arturo Toscanini, Tullio Serafin, and Bruno Walter. He was able to sing the baritone role of Escamillo in Carmen as easily as most baritones. Although he had the lower notes of a bass, they did not have the presence usually associated with the true bass voice, which meant that his Sarastro (The Magic Flute) was not as effective as his Figaro or Don Giovanni. He willingly undertook smaller roles such as Ferrando in Il Trovatore and Colline in La Bohème.