Harvey previously played at Fitch Senior High School in Groton, Connecticut. After being drafted in the third round of the 2007 MLB draft by the Los Angeles Angels, he was drafted again in the 2010 MLB draft by the Mets as the seventh overall pick. In his major league debut on July 26, 2012, against the Arizona Diamondbacks, Harvey set a new club record with 11 strikeouts while earning his first career victory.  Harvey had a breakout season in 2013, being selected to play in his first Major League Baseball All-Star Game. Harvey then missed the entire 2014 season due to Tommy John surgery but returned to top form in 2015, leading the Mets to the pennant. His career, once promising during his first two seasons, has since been derailed by several injuries and ineffectiveness, including Tommy John surgery, thoracic outlet syndrome and a stress fracture in the scapula.
After a 2013 magazine cover compared him to Batman, Harvey and his fans have embraced " The Dark Knight " as his nickname.
Harvey was born in New London, Connecticut; he is the only son and youngest of three children of Ed and Jackie Harvey, both teachers.  He is of Irish and Italian descent.  Harvey was raised in Mystic, Connecticut, with his two older sisters, Jessica and Jocelyn. His father was a standout athlete at Groton, Connecticut's Fitch Senior High School and attended the University of Connecticut where he played both baseball (as a centerfielder)  and football, even appearing in the 1972 College World Series.  After UConn, he eventually returned to Groton to coach his former high school baseball team. 
Harvey grew up as a New York Yankees fan, especially admiring Paul O'Neill and Derek Jeter, whom he has described as a childhood idol of his.   At the beginning of every elementary school year, when asked to write about his life goals, Harvey would write that he wanted to play professional baseball. 
At Fitch Senior High School, Harvey played both baseball (where he was coached by his dad) and basketball. He was teammates with future Major League pitcher Jesse Hahn on both teams.  As a high school freshman, he was able on a few occasions to throw as fast as 90 miles per hour (140 km/h).  Harvey also played summer baseball for numerous travel teams across the country, including the South Florida Bandits, the Midland Redskins, and the East Coast Grays.  As a high school senior, he was selected as a Rawlings First Team All-American and named to their Northeast All-Region First Team.  He was grouped with Madison Bumgarner and Rick Porcello as one of the best pitchers in the 2007 MLB draft and a likely first round pick.   Baseball America ranked him the best high school prospect in 2007.  However, he fell to the Los Angeles Angels in the third round with the 118th overall pick. As the Angels offered only a $1 million signing bonus, Harvey took the advice of his advisors, Bill Caudill and Scott Boras, and opted to sign with the UNC Tar Heels instead. 
Harvey would go on to pitch three seasons at the University of North Carolina at Chapel Hill, where he majored in sports administration.   During his collegiate career, Harvey went 22–7 with 3.73 earned run average (ERA) in 2382⁄ 3 innings pitched.  He ranks ninth all-time in UNC history in strikeouts (263) and 10th in wins (22). 
Harvey spent the summers of ’08 and ’09 pitching for the Chatham Anglers of the Cape Cod Baseball League. Harvey was a key component of the Anglers’ 2008 bullpen, completing the season with a 0.83 ERA, the lowest on the team, pitching 212⁄ 3 innings and striking out 29 of 92 batters faced. Harvey returned to Chatham in 2009 after a difficult sophomore year on the mound. As Harvey explains, he had lost some of the mechanics and flexibility that had made him such a great pitcher throughout high school and the beginning of his college career. Although his ’09 summer was not as impressive as the previous one, his time on the Cape helped him return to the basics and set him on the road to becoming the seventh overall draft pick in the 2010 first year player draft. According to his pitching coach at UNC, Scott Forbes, Harvey returned from the 2009 Cape League season with "a more professional approach."
Harvey was selected as the seventh overall pick by the New York Mets in the 2010 Major League Baseball First-Year Player Draft.  Harvey was listed at 6' 4" and 210 lbs, batting and throwing right-handed.  
In 2011, Harvey's first professional season in the Mets minor-league system, he split time between the single-A St. Lucie Mets and the Double-A Binghamton Mets. With St. Lucie in the Florida State League (FSL), he went 8–2 with a 2.37 ERA and recorded 92 strikeouts in 76 innings.  His performance garnered him two FSL Pitcher of the Week awards and he was selected as a FSL Mid-Season All-Star.  Although selected to appear in the FSL All-Star game, Harvey did not pitch because he was promoted to Double-A Binghamton. 
In the Eastern League with Binghamton, he went 5–3 with a 4.53 ERA and 64 strikeouts in 59.2 innings. Harvey also pitched in the 2011 All-Star Futures Game, recording a save for the winning U.S. team over the World team. 
Harvey was ranked as the Mets organization's second best prospect in 2012 and the 34th overall best prospect by MLB.com.  He was invited to spring training by the Mets that year but did not make the team. Instead, he was promoted to the club's Triple-A affiliate, the Buffalo Bisons of the International League (IL). 
In the first half of his 2012 season at Triple-A, Harvey went 7–4 with a 3.39 ERA in 18 starts.  That performance earned him IL Mid-Season All-Star honors. His strong pitching, plus injuries to major leaguers Mike Pelfrey and Dillon Gee, put him in contention for the fifth spot in the Mets rotation.  Despite spending more time pitching at Triple-A than other top draft picks — 105 innings, recording a 3.34 ERA and striking out over a batter per inning through mid-July  — the Mets front office (headed by general manager Sandy Alderson) did not want to promote Harvey until his consistency and control were better. 
New York Mets
After an injury to staff ace Johan Santana and replacements to the Mets' major-league rotation failed to turn in quality starts, general manager Sandy Alderson and Mets manager Terry Collins backtracked and decided to promote Harvey to the majors, ending his stay with the Bisons with a 7–5 record and 3.68 ERA.  Harvey stayed in the rotation for the remainder of the season as the fifth starter. 
In Harvey's debut, a July 26 start against the Arizona Diamondbacks at Chase Field in Phoenix, Arizona, he pitched 51⁄ 3 innings, giving up three hits and three walks while recording 11 strikeouts.  Harvey recorded his first major-league strikeout against the first batter he faced, Gerardo Parra of the Diamondbacks.  He then had his first major league hit, a two-out double off of Wade Miley in the top of the following inning.  Harvey set a Mets franchise record for strikeouts in a pitching debut (11) and became the first player in modern baseball history (since 1900) to strike out 10 or more batters and get two hits in his major-league debut.  After the game, Mets manager Terry Collins said: 
"I haven't seen 98 out of a starting pitcher in quite some time. He's lived up to exactly what everybody's talked about."
In his second major-league start, against the San Francisco Giants, Harvey pitched six innings, gave up two earned runs, three walks and struck out seven in his first loss.  His 18 total strikeouts were a Mets record for a rookie over his first two games of his career.  After three straight losses, Harvey was able to earn his second win against the Cincinnati Reds on August 16.  In his next two starts, Harvey got a no-decision and a win against the Rockies and Phillies, respectively.   Both were quality starts and he struck out 15 combined in the games. Over his first 15 at-bats in seven starts, he posted impressive batting numbers with a .462 average, two doubles and three runs batted in (RBIs).
Harvey then went on to lose his next two starts and record a no-decision in his last outing of the season on September 19. Despite more opportunities to pitch, Mets management ended his season due to an innings-pitched limit. He finished his inaugural season with a 3–5 record, a 2.73 ERA over 10 starts in which he pitched 591⁄ 3 innings and recorded 70 strikeouts. He surrendered 42 hits and 26 walks.
Harvey continued to garner accolades for his arm strength and control in 2013. New York sports radio host Mike Francesa has compared Harvey to standouts like Justin Verlander, Andy Pettitte and Curt Schilling. After watching Harvey's first two starts of the 2013 season, during which he struck out 19 in 14 innings, former Mets manager Bobby Valentine said Harvey had the potential to be "the best Met pitcher to ever wear the uniform."  His April performance garnered him Pitcher of the Month honors after he posted a 1.56 ERA with 46 strikeouts in 40.1 innings. Opposing batters hit .153 against him. Dwight Gooden gave him the nickname The Real Deal after he saw him pitch live.
On April 13, Harvey had a no-hit bid through 6 2/3 innings against the Minnesota Twins until Justin Morneau hit a solo home run in the bottom of the seventh inning. On May 7, while pitching with a severe nosebleed Harvey retired the first 20 Chicago White Sox batters he faced until Alex Ríos broke up the perfect game with an infield single. Harvey left the game after nine innings, having surrendered only the one hit, as the Mets won in 10 innings.  He was subsequently featured on the cover of the May 20, 2013 issue of Sports Illustrated magazine, dubbed "The Dark Knight of Gotham."  On June 18, Harvey took another no-hitter into the seventh inning, but was stymied by an infield single off the bat of the Atlanta Braves' Jason Heyward.  Harvey notched a career-high 13 strikeouts in the game, giving up three hits over seven innings. 
As the mid-season All-Star break approached, team management talked about limiting Harvey's innings to ensure his pitching health. Harvey had thrown 117 innings in 17 starts at the time, which put him on a season-long pace for 240–250 innings. Mets manager Terry Collins said Harvey would not be allowed to pitch more than 215–220 innings.  
Harvey was the starting pitcher for the 2013 MLB All-Star Game, which took place at the Mets' home ballpark, Citi Field in which he pitched the first two innings.  On August 7, Harvey pitched his first career complete game shutout, giving up four hits and striking out six in a 5–0 win over the Colorado Rockies.  On August 26, Harvey was diagnosed with a partial tear of the ulnar collateral ligament in his right elbow and was placed on the disabled list.  He had logged 178 1/3 innings at that point.
On September 17, Harvey said he would try rehab before opting for surgery.  But the Mets announced on October 4 that Harvey would have Tommy John surgery to repair his right elbow. Because of the procedure, Harvey was expected to miss the entire 2014 season.  Harvey finished this past season 9–5 with a 2.27 ERA in 26 starts with 191 strikeouts in 178 1/3 innings. It was later announced that Harvey had finished tied for 4th in the Cy Young Award, losing to Los Angeles Dodgers pitcher Clayton Kershaw. 
On October 22, 2013, Harvey underwent successful Tommy John surgery to replace the partially torn ulnar collateral ligament in his right elbow. Dr. James Andrews performed the operation in Gulf Breeze, Florida.  Exactly 4 months after his Tommy John surgery Harvey was throwing a baseball for the first time since his injury occurred. He threw 20 times at a distance of 60 feet at the Mets spring training site Port St. Lucie, Florida, with the Mets goal being that he would be ready for the start of the 2015 season. 
In March, Harvey dismissed the idea that he would not pitch until the start of the 2015 season by posting on Twitter that "2014 Harvey Day will happen".  He also told reporters around the same time that he was looking to return around September 2014.  But in June of that same year the Mets officially declared that Harvey would not be pitching until the beginning of the 2015 season. Harvey had been rehabbing at such an accelerated pace that they thought it would be better to take a more cautious approach. After talking with Mets doctors, general manager Sandy Alderson decided that slowing Harvey's path would be best. Another factor was that the Mets at the time were out of playoff contention, and him pitching in meaningless games was not worth the risk of being injured again. 
On April 9, Harvey returned from surgery, and allowed no runs in six innings while striking out nine against the Washington Nationals. After the game, Nationals outfielder Bryce Harper said: "He's going to be a Cy Young one day and everybody knows that. He's one of the toughest at-bats I've ever had."  On May 4, Hall of Fame pitcher and former Mets ace Pedro Martínez said that he believed that Harvey could have a better career than his own. He added, "I think he has more talent than I do." 
On May 18, Harvey pitched 8 innings, giving up no runs against the St. Louis Cardinals while striking out 9.  On May 23, Harvey had the worst start of his career, surrendering 7 runs to the Pittsburgh Pirates in four innings. Due to this poor outing, Harvey's ERA jumped from 1.98 to 2.91.  On July 11, Harvey hit his first career home run against the Arizona Diamondbacks' Patrick Corbin. Harvey also pitched 7 innings, striking out 9, and got his 8th win on the season. 
In September, Harvey's agent, Scott Boras, publicly expressed concern with the Mets' stated plans to allow Harvey to pitch around 190 innings in the regular season, and also pitch "a reasonable amount" in the postseason. Boras suggested that better medical advice, allegedly given by Dr. James Andrews, was to cap the innings at 180, and no postseason activity.   Harvey initially appeared to agree with Boras,  in contrast with his cultivated image of toughness and desire to compete and win at all costs, including having previously objected to efforts by the Mets to both proceed cautiously in his recovery with respect to the timetable for his return (in 2014 Harvey expressed a desire to come back from the injury early, while the Mets followed a conventional recovery timetable  ), and curtail his innings in 2015 by employing a six-man rotation.    After backlash against Harvey's initial comments from Mets fans and the media,  Harvey wrote in The Players' Tribune that the innings limit only applied to the regular season and that he would pitch in the playoffs. 
On October 12, 2015, Harvey pitched against the Los Angeles Dodgers in Game 3 of the NLDS. Though he struggled a bit he was still able to get the win, he gave up 3 runs (2 earned), 7 hits & 2 walks, he also struck out 7 in the Mets' 13-7 win.
Harvey pitched well in Game 1 of the National League Championship Series against the Chicago Cubs. He started Game 1 of the 2015 World Series against the Kansas City Royals, giving up 3 earned runs through 6 innings in a no-decision. Kansas City won the game, 5-4 in 14 innings, to take the series lead.
In Game 5 of the World Series against the Royals, Harvey entered the mound with a 2-0 lead in the top of the ninth inning, per his own request, to try and finish the game despite having thrown over 100 pitches. After allowing a leadoff walk followed by an RBI double, Harvey was pulled. The game-tying run eventually scored later in the inning on a throwing error, resulting in a no-decision for Harvey in a game the Mets would eventually go on to lose in 12 innings. This loss made Kansas City the 2015 World Series Champions.
After making the Mets' Opening Day roster, Harvey lost his first two starts of the 2016 season. During his first start on Opening Day against the reigning World Series champions, the Kansas City Royals, he allowed 4 runs (3 earned) and did not seem his typical self, striking out few batters and surrendering a large amount of hits. After observing Harvey pitch, it seemed that his typical velocity and command had disappeared. Throughout the early part of the season, Harvey seemed to be struggling and inconsistent. However, Harvey had a few quality starts, including one where he went 7 complete innings while striking out 7 against the Chicago White Sox, and one against the San Diego Padres where he struck out a season high 10 and surrendered only 2 runs throug 6 innings. However, he was not pitching as successfully as he was his previous season. Mets pitching coach Dan Warthen said early in the season that Harvey had been struggling with a mechanical problem with his slider during his first two starts.
Throughout the 2016 season, it was believed Harvey was struggling mechanically. However, on June 15, he was placed on the 15-day disabled list with shoulder pain.  Harvey later opted to have season-ending surgery to resolve a condition called thoracic outlet syndrome. Harvey commented on his season-ending surgery, "I'm disappointed in the way I pitched, and hope this cures me, and we get back on track." Harvey ended the 2016 season with a 4-10 record and a 4.86 ERA in 17 starts.  Harvey was the recipient of the 2016 Lou Gehrig Memorial Award.
Coming back from surgery to correct his thoracic outlet syndrome, Harvey began the season 2-0 with a 2.84 ERA in his first four starts.  His struggles from 2016 then began to carry over to 2017, as he pitched poorly in the months of May and June. On May 7, 2017, Harvey was suspended for three games for violating team rules.  It was later revealed that Harvey did not show up to Citi Field the day before and was suspected to have been out late at night partying.  Mets officials were sent over to Harvey's apartment to check on his welfare.  On June 15, 2017, Harvey was placed on the disabled list with a stress fracture in his scapula that required surgery as he was ruled out for 6–8 weeks.  Prior to the injury, he was 4-3 with a 5.25 ERA in 13 starts.  Harvey was activated from the DL on September 2 to face the Houston Astros, giving up seven runs in two innings.  He ended the season with a 5–7 record and 6.70 ERA. 
Awards and honors
- MiLB.com Organization All-Star (2011)
- All-Star Futures Game Selection (2011)
- Florida State League Mid-Season All-Star (2011)
- 2x FSL Pitcher of the Week (April 18 and May 31, 2011)
- International League Mid-Season All-Star (2012)
- National League Player of the Week (April 8–14, 2013) 
- National League Pitcher of the Month (April 2013)
- All-Star selection (2013)
- National League Comeback Player of the Year (2015)
- Lou Gehrig Memorial Award (2016)
Harvey is a power pitcher with a 6-foot-4-inch (1.93 m), 225-pound (102 kg) frame that is suitable for heavy workloads and can generate great arm speed. He has a four-pitch repertoire that includes a fastball, slider, curveball and change-up.
He throws his fastball in both four-seam and two-seam varieties, where it is consistently in the range of 93–96 miles per hour (150–154 km/h) (tops out at 98 miles per hour (158 km/h)) with movement; it is considered a plus pitch.  Harvey usually relies on his slider, which comes in at 88–92 miles per hour (142–148 km/h) and at times is a plus pitch. It gets good rotation and tilts when thrown well, but will occasionally flatten out. In high school, Harvey's curveball was an overhand power curve that had plus potential, but he doesn't throw it frequently in the majors because he favors the slider. Harvey's fourth option is the change-up, which he commands well in the range of 86–88 miles per hour (138–142 km/h). His change-up is considered an average pitch.
Harvey is a passionate New York Rangers fan and frequently attends their games at Madison Square Garden. He has been described as perhaps their most prominent and identifiable fan.  However, his experience as a hockey player is limited to casual roller hockey and ice hockey at a cousin's backyard rink in Vermont.  He is also a fan of the New England Patriots. 
Harvey has a high profile in the media.  He is known to live a flashy lifestyle, drives an expensive Maserati sports car,   has been described as a "lothario" due to his record of dating fashion models, and is frequently mentioned in celebrity gossip columns in New York media.    In May 2013, Matt Harvey began dating model Anne Vyalitsyna after meeting her at a New York Rangers game.  They broke up in February 2014.  In 2015, he began dating Polish model Ania Cywinska.  Harvey and Cywinska broke up in October 2015 right around the time that Harvey missed a New York Mets team workout.  In March 2017, Harvey was spotted kissing Brazilian supermodel Adriana Lima at the River Yacht Club in Miami, Florida.   Harvey and Lima's fling was short-lived however, as Lima was spotted partying with her ex-boyfriend and NFL wide-receiver, Julian Edelman, in May 2017.  Harvey was reportedly an "emotional wreck" after seeing photos of Lima and Edelman together, which resulted in him failing to show up at Citi Field for a Mets game and receiving a three day suspension from the team.    He also appeared nude in The Body Issue of ESPN The Magazine in 2013. 
Harvey appeared on the cover of the May 20, 2013 issue of Sports Illustrated magazine, dubbed "The Dark Knight of Gotham,"  a play on Batman's home city, its association with New York City and the recent Dark Knight film trilogy. Harvey, who had been a Batman fan since childhood,  as well as teammates, fans, the Mets and other media sources immediately embraced the comparison.     Harvey even had "Dark Knight" carved into the knobs of his bats to begin the 2015 season before replacing it with a personalized hybrid Harvey-Batman logo, versions of which had previously appeared on his locker and on T-shirts.    Early in the 2013 season, fans, media and teammates also began referring to any day on which Harvey is scheduled to start as "Harvey Day."   Harvey has said that his best friend on the Mets is fellow starting pitcher and rotation mate, Jacob deGrom.