A three-time MLB All-Star, he played for the Florida Marlins, the Boston Red Sox, and the Los Angeles Dodgers.

[1] He also raised his GPA and was able to get back on the team, where he had a 9–3 record with a 1.18 earned run average (ERA) as a sophomore, tossing three no-hitters.

"[3] In his senior season, Beckett, by this point nicknamed "Kid Heat,"[1] was named the High School player of the year by USA Today.

[4] Beckett signed a letter of intent to pitch for Texas A&M University,[5] but he and Josh Hamilton were seen as the top two players available in the 1999 Major League Baseball draft.

[9] Beckett impressed the Marlins in his first spring training with the team in March 2000, with a fastball clocked at 94–96 miles per hour (151–154 km/h) and a good curveball.

[23] He subsequently went on the disabled list (DL) with a sprained right elbow in mid-May, part of a string of team injuries that contributed to the firing of Manager Jeff Torborg.

[25] Beckett made his postseason debut in the opening game of the 2003 National League (NL) Division Series, where he allowed only one run in seven innings against the San Francisco Giants but picked up the loss as Jason Schmidt pitched a complete-game shutout.

[30] In game seven, on two days rest, Beckett came in out of the bullpen to pitch four innings and the Marlins won 9–6 to clinch the National League championship.

[31] Beckett won the 2003 World Series MVP Award with two strong performances, one of which was on three days' rest, as the Marlins defeated the New York Yankees.

[35] In a deal that was made official on Thanksgiving Day 2005, Beckett was traded to the Boston Red Sox along with third baseman Mike Lowell and relief pitcher Guillermo Mota for minor league shortstop Hanley Ramírez (the top prospect in the Red Sox system at the time) and pitchers Aníbal Sánchez, Jesús Delgado and Harvey García.

[15] After a strong first half, posting a 12–2 record with a 3.44 ERA, he was selected to the American League team in the 2007 MLB All-Star Game.

[43] Beckett threw a shutout against the Anaheim Angels on 108 pitches, 83 of which were strikes, to start the 2007 American League Division Series.

[45] He then started and won the first game of the 2007 World Series against the Colorado Rockies, pitching seven innings, allowing one run on six hits, and striking out nine batters.

[46] On May 8, 2008, Beckett recorded his 1,000th career strikeout, when Brandon Inge of the Detroit Tigers struck out swinging in the seventh inning.

[21] In game three of the 2008 American League Division Series against the Anaheim Angels he allowed four runs in five innings[48] He then made two starts in the 2008 ALCS against the Tampa Bay Rays and was 1–0 but had a high 9.64 ERA.

[49] In 2009, during his first Opening Day start with the Red Sox, Beckett struck out 10 through seven innings allowing only one run and two hits in a 5–3 victory over the Rays.

[50] On April 14, 2009, MLB fined and suspended him six games for intentionally throwing over the head of Angels outfielder Bobby Abreu.

[52] On June 20, 2009, he recorded his first complete-game shutout in three years against the Atlanta Braves in a duel against former Red Sox pitcher Derek Lowe.

[54] Beckett recorded his 100th career win on July 12, 2009, pitching a complete-game shutout against the Kansas City Royals at Fenway Park.

[55] On August 7, 2009, against the New York Yankees, he engaged in a pitching duel with former Marlins teammate A. J. Burnett that turned into a fifteen-inning, five-hour-and-thirty-three-minute game.

The Red Sox eventually lost the game in the bottom of the 15th, when Alex Rodriguez hit a walk-off two-run home run.

This was the first time a Major League pitcher had that combination of stats in a single game since Jack Coombs of the Philadelphia Athletics during the 1911 season.

[60] On September 16, he recorded his 1,000th strikeout as a member of the Red Sox against Tampa Bay's Ben Zobrist in the sixth inning.

[21] He was also the center of yet another controversy when it was reported that he played several rounds of golf despite having been scratched from his start due to a lat muscle injury.

[21] On August 25, 2012, Beckett was traded to the Los Angeles Dodgers (along with Adrián González, Carl Crawford and Nick Punto and $11 million in cash) for James Loney, Iván DeJesús, Jr., Allen Webster, and two players to be named later (Jerry Sands and Rubby De La Rosa).

[66] While on the disabled list, he began to experience numbness and tingling in his hand so he went to see a nerve specialist and expressed doubt as to whether he would be able to pitch again.

The Dodgers shut him down from pitching for a month while he underwent a rigorous rehabilitation program in an effort to avoid season-ending surgery.

[80] An MRI revealed that his hip impingement had resulted in a torn labrum and two cysts, possibly requiring season ending surgery.

[91] He was featured in a Kevin Fowler music video alongside his teammates John Lackey, Tim Wakefield, Jon Lester and Clay Buchholz.

[92] On November 11, 2017, Beckett was arrested for public intoxication as a result of charging at a country band at a local bar in Texas.