Unfortunately, by the 1930s, Pizzetti's opera output suffered from strict adherence to his own music-dramatic theories that he had developed by 1908. As his style had not matured, his works became dogmatic and repetitive. Along with Respighi and other reactionaries, he even signed a notorious manifesto on December 17, 1932, attacking the progressive trends of the time and recommending a return to tradition. After World War II, he experienced somewhat of a renewal in creativity, finding success with Ifigenia (1950) and Assassinio nella cattedrale (1958), but his finest operatic writing was still that from his early career.
In addition to opera, Pizzetti also wrote other vocal compositions as well as instrumental and orchestral works. He was further known as a music critic, conductor, music school professor, and administrator. From 1908 to 1924, he lived in Florence, a city that provided him with much intellectual and artistic stimulation and which led him to become active as a critic. Most importantly, he became a writer for the famous Florentine La voce, through which he associated with many influential Italian philosophers and artists gathered around that periodical. Later in life, he wrote for other journals such as La rassegna musicale (1932 - 1947) and the Corriere della sera (from 1953). As a professor, he taught at the Parma Conservatory (1907) and the Istituto Musicale of Florence (1908), becoming the latter school's director in 1917. By 1924, he was leading the Milan Conservatory, then in 1936 he moved to Rome to head the advanced compositional course at the Accademia di Santa Cecilia, of which he was president from 1947 to 1952. As if that were not enough hats for him to wear, Pizzetti became increasingly active as a conductor from about 1930 in the Americas as well as in Europe.
Obviously, Pizzetti led a very active and varied musical life well into the 1960s and never merely as a composer. Though relatively unknown outside of Italy, Pizzetti's compositions were, and still are, significant in his own country, and a good amount of scholarship has been written about his life and work.