Laporte scored his first goal for City on 25 August 2018, equalising against Wolverhampton Wanderers in a 1–1 away draw. He made 51 appearances during the 2018–19 season as the club completed the first domestic treble in English football history (Premier League, FA Cup, League Cup, plus the Community Shield). He scored five goals throughout the season, including an important goal on the final day of the Premier League campaign as City romped to victory over Brighton and Hove Albion securing back-to-back league titles and the second of Laporte's career. Overall he played a total of 4,352 minutes.