Painter born in Siena in 1583. We have no information of his first artistic training. On the basis of his few paintings and many miniatures, he was considered a "pupil" of the Sienese painter Vincenzo Rustici (Romagnoli, 1835, p. 89); but it has also been suggested that he was a disciple of the Flemish painter, Bernardo Rantwyck, active in the Tuscan. We also know that, alongside his pictorial production, G. devoted himself to the creation of ephemeral apparatuses, so much so that he was also given the title of "plastic" (Ugurgieri Azzolini).

In 1604 G. lived in the parish of S. Donato and by this date he must have already been married, since we know that a son named Taddeo.

G. died in Siena in July 1646 and was buried in the tomb of his family, in the church of Carmine.