See studies by E. F. Kenton (1967) and D. Arnold (1979).
In 1562 he went to Germany, where he visited Frankfurt am Main and Munich; while there he met and became friends with Orlande de Lassus, one of the most wide-ranging composers of the entire Renaissance, who wrote secular songs in French, Italian, and German, as well as abundant Latin sacred music. This musical relationship was immensely profitable for both composers: while Lassus certainly learned from the Venetian, Gabrieli took back to Venice numerous ideas he learned while visiting Lassus in Bavaria, and within a short time was composing in most of the current idioms, including one which Lassus entirely avoided: purely instrumental music.
In 1566 Gabrieli was chosen for the post of organist at St. Mark's, one of the most prestigious musical posts in northern Italy; he retained this position for the rest of his life. Around this time he acquired, and maintained, a reputation as one of the finest current composers. Working in the unique acoustical space of St. Mark's, he was able to develop his unique, grand ceremonial style, which was enormously influential in the development of the polychoral style and the concertato idiom, which partially defined the beginning of the Baroque era in music.
His duties at St. Mark's clearly included composition, for he wrote a great deal of music for ceremonial affairs, some of considerable historical interest. He provided the music for the festivities accompanying the celebration of the victory over the Turks in the Battle of Lepanto (1571); he also composed music for the visit of several princes from Japan (1586).
Late in his career he also became famous as a teacher. Prominent among his students were his nephew Giovanni Gabrieli; the music theorist Lodovico Zacconi; Hans Leo Hassler, who carried the concertato style to Germany; and many others.
The date and circumstances of his death were not known until the 1980s, when the register containing his death date was found. Dated August 30, 1585, it includes the notation that he was "about 52 years old"; his approximate birth date has been inferred from this. His position at St. Mark's was not filled until the end of 1586, and a large amount of his music was published posthumously in 1587.
His early style is indebted to Cipriano de Rore, and his madrigals are representative of mid-century trends. Even in his earliest music, however, he had a liking for homophonic textures at climaxes, foreshadowing the grand style of his later years. After his meeting with Lassus in 1562, his style changed considerably, and the Netherlander became the strongest influence on him.
Once Gabrieli was working at St. Mark's, he began to turn away from the Franco-Flemish contrapuntal style which had dominated the music of the 16th century, instead exploiting the sonorous grandeur of mixed instrumental and vocal groups playing antiphonally in the great basilica. His music of this time uses repetition of phrases with different combinations of voices at different pitch levels; although instrumentation is not specifically indicated, it can be inferred; he carefully contrasts texture and sonority to shape sections of music in a way which was unique, and which defined the Venetian style for the next generation.
Not everything Gabrieli wrote was for St. Mark's, though. He provided the music for one of the earliest revivals of an ancient Greek drama in Italian translation: Oedipus tyrannus, by Sophocles, for which he wrote the music for the choruses, setting separate lines for different groupings of voices. It was produced at Vicenza in 1585.
Evidently Andrea Gabrieli was reluctant to publish much of his own music, and his nephew Giovanni Gabrieli published much of it after his uncle's death.