Halladay was the Blue Jays' first draft selection in the 1995 MLB draft, the 17th pick overall, and played for the team from 1998 through 2009, after which he was traded to Philadelphia. Halladay was known for his ability to pitch deep into games effectively and, at the time of his retirement, was the active major league leader in complete games with 67, including 20 shutouts.

On May 29, 2010, Halladay pitched the 20th perfect game in MLB history, beating the Florida Marlins by a score of 1–0. On October 6, 2010, in his first postseason start, Halladay threw the second no-hitter in MLB postseason history (Don Larsen's perfect game in the 1956 World Series being the first) against the Cincinnati Reds in Game 1 of the 2010 NLDS.

It was his second no-hitter of the year (following the May 29 perfect game), making Halladay the fifth pitcher in major league history (and the first since Nolan Ryan in 1973) to throw multiple no-hitters in the same season. During the 2012 season, he became the 67th pitcher to record 2,000 strikeouts. Halladay was also one of six pitchers in MLB history to win the Cy Young Award in both the American and National Leagues.

On November 7, 2017, Halladay died after his ICON A5 amphibious plane crashed into the Gulf of Mexico off the coast of Florida.

This Rawlings official MLB baseball was signed in blue ballpoint pen by Halladay and includes a Great Moments COA.