The celebrated athlete died Tuesday after he crashed his plane into the Gulf of Mexico near Holiday, Florida.
Following the news of the tragedy, nearly everyone who had ever played alongside the pitcher -- or against him -- took to social media to share their memories, post tributes, and send condolences to Halladay's widow, Brandy, and their two sons, Ryan and Braden.
St. Louis Cardinals pitcher Chris Carpenter -- one of Halladay's former teammates when they both played for the Toronto Blue Jays and a close friend -- released a statement on his passing.
"We grew up together. Went through good and bad times together. He was an amazing pitcher, competitor, teammate and friend," Carpenter shared. "I have so many memories with him and his family. I will miss him."
The pro also paid tribute on Twitter, writing, "When people ask me if I could re-live any moment in baseball-1 that I always say would be to watch Doc pitch again! Today my heart goes out to Brandy and the boys. He was a great husband, father, friend and teammate. Such a special man! You will be forever missed!"
When people ask me if I could re-live any moment in baseball-1 that I always say would be to watch Doc pitch again! Today my heart goes out to Brandy and the boys. He was a great husband, father, friend and teammate. Such a special man! You will be forever missed! #RoyHalladay
Halladay's career spanned 15 years, during which time he pitched for the Toronto Blue Jays -- from 1998 to 2009 -- and then for the Philadelphia Phillies until his retirement in 2013.
The eight-time All-Star racked up an impressive legacy during his years on the mound, including two Cy Young Awards, making him one of only six players ever to win the coveted honor in both the American League and the National League.
In May 2010, Halladay made history when he pitched a perfect game against the Florida Marlins -- a feat that has only been accomplished 21 times in the history of modern baseball.
Later that season, he became only the second player ever to pitch a no-hitter in the post-season, against the Cincinnati Reds. The epic demonstrations marked the very first time a pitcher has ever thrown both a perfect game and a no-hitter in the same season.
His raw statistics speak to just how amazing he was as a pitcher. Halladay threw 67 complete games during his career, 49 of which he pitched during his 11 seasons playing for the Blue Jays. Since he left, the entire pitching rotation for the Blue Jays have pitched a combined total of 33 complete games. And these are just some of the mind-blowing statistics that show what a competitive and talented ballplayer he really was.
However, it seems that Halladay's real legacy isn't just his impressive skill. Instead, the beloved pitcher is being remembered for his true and endearing decency.
From motivating his teammates to strive to always be better and work harder to inspiring hope in young kids who want to one day pursue their passions, Halladay is remembered for being a truly remarkable human being.
Seattle Mariners catcher Carlos Ruiz, who played with Halladay on the Philadelphia Phillies, shared, "Roy was one of the greatest pitchers I ever caught and an ever better person and friend. I wanted to win more for him than myself. I will miss him very much."
From having the Blue Jays turn a box suite into a place for kids from the Children's Hospital to come watch games to meeting with he young fans and making their visits to the ballpark a truly special experience, Halladay worked tirelessly to make a difference.
While in Toronto, Roy Halladay had the Blue Jays turn a suite into "Doc's Box" for kids from the Hospital for Sick Children. They remodeled it to make it more kid-friendly.
From players who competed alongside Halladay for years to pros who only saw him when they were trying to hit his pitches, nearly everyone who ever walked out on a baseball diamond honored the late legend.
Check out the slew of heartfelt tributes from pros, fans and even other MLB teams who paid their respects.
RIP Roy Halladay.. a Toronto legend! Growing up I used to love watching Doc play, sad day for Toronto sports fans
Beyond gifted, but never spoke of it. Inspired with action, not words. Never compromised, backed down, or judged. Always respectful. Ever-kind. Genuinely humble. Quiet. Honest. Sincere. Caring. A Timeless example.
I’ll never forget Aug ‘13. Doc and I were two months away from retirement. He was hurt, clearly. He was still pitching tho. One day in Wrigley he was throwing 83, and all over the place. I go to the mound and he just said “everything hurts.” He wouldnt come out. Always fighting.
According to baseball columnist Jeff Passan, "On the day Roy Halladay retired, he said: 'My goal is to try and leave baseball better than I found it.' That's the essence of who he was."
It seems that Halladay's goal outside of baseball was to leave the world a better place than he found it, and from the outpouring of tears, adoration, admiration and love, it's clear the sports icon did just that.