On April 30, 2002, Leiter became the first Major League pitcher to defeat all 30 teams, after beating the Arizona Diamondbacks 10–1. Leiter would pitch for the Mets until the end of the 2004 season. In his seven seasons in a Met uniform, all wearing number 22, he went 95–67 with a 3.42 ERA. At the time he left the Mets, he ranked highly on several Mets all-time lists including wins (6th), strikeouts (7th with 1106), innings pitched (7th with 1360.0), and games started (6th with 213). He was the Mets Opening Day starting pitcher in 1999, 2001, and 2002.