He received his first ever call-up to the senior team by head coach Vincenzo Montella ahead of the home Serie A game against Roma, which was played on 7 May 2017.

[8] Gabbia stayed with Milan for the 2019–20 season as a squad player behind the likes of Alessio Romagnoli, Mateo Musacchio, and Simon Kjær.

[14][15] On 3 January 2024, amid the injury crisis that severely affected AC Milan's central defense, the club recalled Gabbia from his loan.

[16][17] He finished the season with 25 more appearances, 3 goals, and positive reception from the press and fans alike, prompting the club's management to remove him from the outgoing transfer list and start negotiations to upgrade his contract.

[18] On 22 september 2024 he scored a last minute goal in a 2–1 win against Inter milan on the Derby della madonnina Gabbia represented Italy at the 2016 UEFA European Under-17 Championship, where the team did not advance from the group stage.