Massolo started his career with
Sampdoria, where he was part of their youth system and was also handed a first-team number during the
2014–15 season. He was successively loaned out to
Serie D amateurs
Sanremese, with whom he made his senior debut as a player, marking a total 32 appearances and 12 clean sheets during his stay at the club. After being released by Sambenedettese, he joined Serie C club
Fermana in October 2020; In July 2021, Massolo signed for Serie C fallen giants
Palermo, his signing being explicitly requested by head coach
Giacomo Filippi, who had worked with him during his days as
Roberto Boscaglia's assistant at Virtus Entella. Originally signed as an understudy to first choice goalkeeper
Alberto Pelagotti, he started being occasionally featured in the starting lineup under new head coach
Silvio Baldini, who then promoted him as the first choice goalkeeper for the promotion playoffs, which Palermo eventually won. On 18 July 2023, after a single Serie B season as a reserve to
Mirko Pigliacelli and no first-team appearances, Massolo left Palermo on a permanent transfer to join
Serie C club
Vicenza. ==Career statistics==