Over his 16-year Major League career, Halladay was one of the most feared pitchers in the game, finishing his career with a 203-105 record and a lifetime ERA of 3.38.
The former first-round draft pick was selected 17th overall by Toronto in 1995, and won his first of two Cy Young trophies less than a decade later in 2003.
He eventually spent 12 seasons with the Blue Jays, before joining the Phillies in 2010 for the last four years of his stellar career.
Over his 2,749 1/3 innings pitched in the big leagues, Halladay struck out 2,117 batters and amassed a remarkable 67 complete games, 20 of which were shutouts.
Halladay was an eight-time All-Star, eclipsed 220 innings pitched in eight different seasons, and averaged 17 wins per year from 2002 to 2011.
Yankees fans saw plenty of the dominant 6-foot-6 right-hander from 1998 through 2009, when he was among the best pitchers in the AL East year after year during his Blue Jays career. He finished among the top-five in Cy Young voting seven times in his career, winning one in the AL in 2003, and one in the NL in 2010.
In 2010, Halladay became just the second pitcher in history after Yankees legend Don Larsen to throw a no-hitter during the postseason.
"We are numb over the very tragic news about Roy Halladay's untimely death," the Philadelphia Phillies wrote in a statement Tuesday. "There are no words to describe the sadness that the entire Phillies family is feeling over the loss of one of the most respected human beings to ever play the game. It is with the heaviest of hearts that we pass along our condolences to Brandy, Ryan and Braden."