He began to write for the stage in 1639 (Le nozze di Teti e di Peleo) soon after the first public opera house opened in Venice. He established so great a reputation that he was summoned to Paris in 1660 where he revived his opera Xerxes. He visited Paris again in 1662, producing his Ercole amante. He died in Venice at the age of 73.
Cavalli introduced melodious arias into his music and popular types into his libretti. His operas have a remarkably strong sense of dramatic effect as well as a great musical facility, and a grotesque humour which was characteristic of Italian grand opera down to the death of Alessandro Scarlatti. Cavalli's operas provide the only example of a continuous musical development of a single composer in a single genre from the early to the late 17th century in Venice — only a few operas by others (e.g. Monteverdi and Antonio Cesti) survive. The development is particularly interesting to scholars because opera was still quite a new medium when Cavalli began working, and had matured into a popular public spectacle by the end of his career.
Cavalli wrote thirty-three operas, twenty-seven of which are still extant, being preserved in the Biblioteca Nazionale Marciana (Library of St Mark) at Venice. Copies of some of the operas also exist in other locations. In addition, nine other operas have been attributed to him, though the music is lost and attribution impossible to prove.
In addition to operas, Cavalli wrote settings of the Magnificat in the grand Venetian polychoral style, settings of the Marian antiphons, other sacred music in a more conservative manner (notably a Requiem Mass in eight parts [SSAATTBB], probably intended for his own funeral), and some instrumental music.