Gattoni spent his early years at local team Club Chacabuco, before signing for
San Lorenzo at the age of seven. He made his breakthrough into first-team football in October 2020, appearing for his senior debut in a goalless draw away to
Argentinos Juniors in the
Copa de la Liga Profesional on 31 October. He had been an unused substitute once in each of the preceding two years; for a
2018 Copa Sudamericana loss to
Deportes Temuco and for a 2019
Primera División win over
Godoy Cruz, with a debut being further delayed due to serious cruciate injuries suffered in both knees in 2017 and 2018. Gattoni scored his first senior goal on 14 November 2020 against
Aldosivi. On 3 July 2024, Gattoni joined
River Plate on loan with the option to buy. ==International career==