[1] He was born in Orvieto as the son of the flemish musician Franceso Fabri, who also had been his first teacher of music.
His son Stefano Fabri jr. had been the teacher of Francesco Beretta - also a director of music at the Vatican.
[2][3] His career began at the cathedral of his birth place in Orvieto.
In 1599 he left his position in Orvieto to succeed Ruggiero Giovanelli[1] but they also seem to have been Co-workers.
Besides his function also a director of music at the Vatican, the Lateran and S. Loreto, where he stayed until the end of his life, he also composed for S. Luigi dei Francesi and S. Maria Maggiore.