Although he was not an international conducting star, Gianandrea Gavazzeni was one of the most respected and dependable of opera conductors, considered one of the great preservers of the authentic Verdi tradition at La Scala. He was also a composer, but renounced that career.

At the age of 11 he entered the Accademia di Santa Cecilia in Rome, studying piano there from 1921 to 1924. In 1925, he entered Milan Conservatory, remaining there through 1931. His primary area of study was composition, mainly under Ildebrando Pizzetti.

He started his musical career in the traditional entry-level job of répétiteur (i.e., individual coach who ensures that singers are prepared according to the conductor's interpretation), as a pianist, and as a journalist in the field of music.

When he had an opportunity to conduct, he began to champion the music of his fellow composers Pizzetti, Luigi Dallapiccola, Gian-Francesco Mailipiero, and Goffredo Petrassi, the leading modernists on the Italian scene at the time, having also supported them in his journalistic writings.

Gavazzeni composed actively at this time. His oratorio Canti per Sant'Alessandro (1934) and an opera, Paolo e Virginia (1935), were performed and well received. He wrote additional orchestral and vocal music. But in 1949, as his conducting career was taking off, he not only announced his retirement as a composer, but also banned any further performances of his works.

In 1948 he first conducted at La Scala Opera in Milan, where he continued to conduct frequently through 1977. He was the artistic director of that house from 1965 to 1972. He also often conducted at Maggio Musicale of Florence. His British debut was at the 1957 Edinburgh Festival, conducting a guest appearance of the smaller La Scala touring company called La Piccolo Scala. He appeared at the Glyndebourne Festival Opera in 1965, leading Anna Bolena by Donizetti, and at the Metropolitan Opera (his U.S. debut) in 1976. He conducted widely in Europe, including several appearances at the Bol'shoi in Moscow, and in Canada and the U.S. He was best known for his interpretations of operas of Rossini, Donizetti, Verdi, and the verismo school.

He continued his notable career as a music journalist. His Musicians of Europe (Musicisti d'Europe, Milan, 1954) was a notable summing up of the immediate post-War classical music scene, and biographical/musical studies of Bellini and Donizetti are also well respected., Rovi