Gentile was born in or near Fabriano, in the Marche. His mother died some time before 1380, and his father, Niccolò di Giovanni Massi, retired to a monastery in the same year, where he died in 1385.
By around 1405, Gentile da Fabriano was working in Venice. He painted a panel for the church of Santa Sofia, now lost; Jacopo Bellini worked perhaps in his workshop. Between 1408 and 1409, he painted a fresco (now lost) in the Doge’s Palace depicting the naval battle between the Venetians and Otto III. In Venice he knew Pisanello and perhaps Michelino da Besozzo. He also produced commissions for other cities during this period, such as his Madonna and Child for a church in Perugia.
On 6 August 1420 he was in Florence, where he painted his famous altarpiece depicting the Adoration of the Magi (1423), now in the Uffizi and regarded as one of the masterpieces of the International Gothic style.
Gentile is known to have died before 14 October 1427. He is commonly said to have been buried in the church now called S. Francesca Romana in Florence, but his tomb vanished; there is evidence, however, that he may be buried in the church of Santa Maria in Trastevere, in Rome, the place of his death.