The 28-year-old had spells at Borussia Dortmund and Chelsea before joining Milan in 2023. The American has recorded 44 goals in 141 appearances for the Rossoneri and finished the 2024-25 season as their top scorer.
"Pulisic's contract extension reflects a shared commitment to building on the progress made together in recent years, with the ambition to keep improving, achieve new milestones and write more memorable chapters in the Club's history," Milan said in a statement.
Pulisic has represented his country at two World Cups and is a four-time winner of the US Soccer Male Player of the Year.