Attacker Camarda took to the field in the 83rd minute at the San Siro aged 15 years, eight months and 15 days, replacing Luka Jovic.
"He's got a lot of talent and intelligence, he knows that he needs to work harder than everyone else," said Milan captain Davide Calabria after the match.
Camarda, who made headlines when he scored a bicycle kick against Paris Saint-Germain in the UFA Youth League, had very little to do as Milan largely defended late-on in Saturday's win.
He beat the previous record held by Bologna defender Wisdom Amey, who made his Serie A debut in May 2022 aged 15 years, nine months and one day.
Camarda was called up from Milan's youth set-up amid a series of absences including Olivier Giroud, Rafael Leao and Noah Okafor.
Milan are third in Serie A, five points behind league leaders Inter Milan who face second-placed Juventus on Sunday.
