Son of a decorator, Gatti moved from Forlì to Florence in 1830. He studied in Florence, enrolling in 1843 in the Academy of Fine Arts. Around the 1850s he achieved his first successes, choosing historico-religious themes for his works. In 1861, he decorated the Throne Room in the Pitti Palace. An important factor for his career was his relationship with the architect Giuseppe Poggi (1811-1901), who was in charge of Florence's urban development and supervised the restoration of many old palaces. Gatti would then be commissioned to prepare the frescoes. He decorated the ceiling of the Verdi Theatre in Pisa, where also painted the curtains: this started a trend that spread to theaters all over the world, from Cairo to Santa Fe de Bogotà.