Born in Naples, Italy, he went to the United States as a steerage passenger on the S/S Auguste Victoria from Naples to New York in 1902, at the age of eighteen. He was associated with companies in Boston and Montreal, and made his debut with the Metropolitan Opera with a production of I puritani, in 1919. His work was seen at the Met until 1934, with Il barbiere di Siviglia, Lucia di Lammermoor, Tosca, Aïda, Madama Butterfly, Rigoletto, Cavalleria rusticana, La bohème, Manon Lescaut, Pagliacci, Zazà, La navarraise, L'oracolo, Il trovatore, La forza del destino, L'amore dei tre re, Manon, Samson et Dalila, Boris Godunov, Faust, Pizzetti's Fra Gherardo, La traviata, Les contes d'Hoffmann, Il signor Bruschino, Lakmé, L'africaine, The Emperor Jones, Simon Boccanegra, Gianni Schicchi, and Roméo et Juliette. Agnini was also on the staff of the San Francisco Opera, and guest-directed in Mexico City, Buenos Aires, Rio de Janeiro, London, Paris, Pittsburgh, Philadelphia, and Chicago.
Hollywood
Maestro Agnini was "Technical Advisor" for the film Metropolitan. Uncredited, he held the same position for Going My Way and The Lost Weekend.
In 1947, Agnini debuted at the New Orleans Opera Association, with Il trovatore, and went on to stage Carmen, Faust, Madama Butterfly, and Samson et Dalila. By 1954, he had joined the Association's staff, and directed La bohème, Otello, Tosca, Lakmé, Rigoletto, Andrea Chénier, Martha, Die Fledermaus, Madama Butterfly, Carmen, Gianni Schicchi, Aïda, Manon, Lucia di Lammermoor, Elektra, L'amore dei tre re, La traviata, Le nozze di Figaro, Falstaff, Cavalleria rusticana, Pagliacci, Werther, Faust, La Cenerentola, Boris Godunov, Il barbiere di Siviglia, Manon Lescaut, Il trovatore, Don Pasquale, Turandot, L'elisir d'amore, Hänsel und Gretel, Norma, Don Giovanni, Les contes d'Hoffmann, and Tannhäuser. An excerpt from Agnini's 1959 production of La bohème was televised in New Orleans, but a kinescope has never been discovered. He died on March 27, 1960, of a heart condition, during rehearsals for his production of Samson et Dalila, in New Orleans, leaving behind his widow and two daughters.