He returned to Florence with a letter of recommendation of Cardinal Gozzadini seeking patronage from Cosimo III de' Medici. He found work in the studio of Tommaso Redi and Sebastiano Galeotti. He travelled to Bologna to work under Felice Torelli and then resettled in Florence in 1715. Ferretti soon joined the Florentine Accademia del Disegno, where he later taught painting but also designed tapestries for the Medici. He found abundant patronage in fresco painting for the Florentine Abbey (Badia Fiorentina), the Chapel of San Giuseppe in the Duomo, and the altar and cupola of the Church of San Salvatore al Vescovo. One of his most important works was the decoration of the ceiling of the Church of Santa Maria del Carmine, since lost in a fire.