Tosti turned professional after graduating in 2018 and joined the
PGA Tour Latinoamérica. In 2019, he won his first title, and in 2022 he won a second title and finished 5th in the Order of Merit, to earn graduation to the
Korn Ferry Tour. He gained media attention after accepting a shuttle ride, believing it was an official courtesy car, from the 18th green to the first tee mid-round at the
LECOM Suncoast Classic, receiving a two-shot penalty for breaking an obscure model local rule that says players may not use transportation during a round. In August 2023, Tosti claimed his first win on the Korn Ferry Tour at the
Pinnacle Bank Championship, also claiming a card for the
2024 PGA Tour season. Two weeks later, he was forced to withdraw from the
Albertsons Boise Open following an undisclosed disciplinary matter. ==Amateur wins==