Fangraphs called Taillon the best high school pitching prospect since Josh Beckett. Baseball America compared him to pitchers like Stephen Strasburg.
Jameson Taillon was born in Lakeland, Florida to Christie and Michael Taillon on November 18, 1991. As he was born in Florida and his parents were born in Canada, Taillon is a dual citizen of the United States and Canada. Taillon attended The Woodlands High School in Texas. He caught the attention of Pirates scouts with a 22–6 high school career record. He was 8–1 his senior year and threw a 19-strikeout no-hitter against rival Conroe High School on March 23, 2010.
Taillon signed a National Letter of Intent with Rice University in November 2009 posing a challenge to the Pirates in their effort to sign him. However, hours before the signing deadline, the Pittsburgh Post-Gazette reported that Taillon had indeed signed with the Pirates. Baseball America's Jim Callis reported that Taillon's deal included a $6.5 million signing bonus, the 2nd highest in draft history.
Taillon made his professional debut with the Pirates' low-A affiliate, the West Virginia Power against the Hagerstown Suns on April 27, 2011. He joined the team on April 24 after staying in Florida for an extended spring training assignment. He was named to appear in the 2012 All-Star Futures Game. He was promoted to the AA Altoona Curve in August 2012. In his first week with the Curve, August 20–26, 2012, Taillon was named the Eastern League pitcher of the week.
Prior to the 2013 season, Taillon was ranked as the 15th best prospect in baseball by MLB.com. Taillon participated in the 2013 World Baseball Classic for Team Canada, being the youngest member of the team at age 21.
Taillon underwent Tommy John surgery in April 2014 to repair damage to the ulnar collateral ligament of the elbow in his throwing arm, costing him the 2014 season, while a sports hernia caused him to miss the 2015 season.
Taillon began 2016 with Triple-A Indianapolis, where he made 10 starts before earning his first major league call-up. Taillon went 4–2 with a 2.04 ERA, striking out 61 in 61.2 innings and walking only 6. On June 8, Taillon was recalled to make a spot start with the Pirates, who decided to push back Francisco Liriano's start one day after they played a doubleheader the day before. Facing off against fellow 2010 first rounder Noah Syndergaard in his debut, Taillon threw 6 innings, giving up 3 runs on 6 hits, 2 walks, and 3 strikeouts, not receiving a decision in the eventual 6-5 loss. After the game, Taillon was optioned back to Triple-A, but not without receiving compliments from his manager Clint Hurdle on his effort, saying "This kid's poured into everything he's done. It's been a great fight back." However, his stay in Indianapolis was very brief, as an injury to Gerrit Cole necessitated a move to bring Taillon back into the rotation. On June 14, Taillon made his second start, also against the Mets, throwing 8 scoreless innings, carrying a no-hitter into the seventh before it was broken up by Curtis Granderson, and recording his first win in the 4–0 victory.
Taillon underwent surgery for testicular cancer on May 8, 2017 and made his first rehab start three weeks later, giving up only one run in three innings.
Taillon stands at 6' 5" and has a fastball that has hit 99 miles per hour (mph) as well as a "plus" curveball according to MLB.com. Pirates general manager Neal Huntington said of Taillon, "He has the stuff that allows you to envision down the road a top-of-the-rotation starter."
Taillon describes his pitch repertoire as being a four-seamer at 94–98 mph, a two-seam fastball at 93–96, a "power" curveball with diagonal break, and a circle changeup. He says of his pitch selection, "I feel pretty confident right now that I can throw pretty much any pitch in any count."