Born in Siena in 1563, Vanni learned his trade in the workshop of his stepfather Arcangelo Salimbeni. He moved to Bologna, where he was the pupil of Bartolomeo Passarotti, in 1575 and then in 1577 to Rome, where he completed his training with Giovanni de Vecchi. His style evolved under the influence of the art of Raphael, Federico Barocci and Annibale Carracci, which combined with the substratum of 16th-century Sienese artistic culture. He returned to Siena in the 1590s and produced numerous works of religious art, including the altar of Sant’Ansano for the Cathedral and the high altar for the church of San Niccolò in Sasso. He died on 26 October 1610 and is buried in Siena in the church of San Giorgio.