Matsuzaka was born on September 13, 1980, in Aomori, Aomori Prefecture. He was named after Japanese high school star pitcher Daisuke Araki. Growing up in Koto, Tokyo, he studied kendo from the age of five to nine and began playing organized baseball when he was in 3rd grade.

Baseball players who were born in the 1980 academic year (from April 2, 1980, to the following April 1, 1981) have been called the “Matsuzaka Generation” in Japan.

During that offseason, his fastballs first began to regularly sit around 87 mph (140 km/h). After pitching his school to the championship of the National High School Baseball Invitational Tournament (Spring Koshien), Matsuzaka set his aim on the 1998 Summer Koshien and eventually led his school to the championship.

On May 16, 1999, when Matsuzaka was in his rookie season at age 18, he first faced Ichiro Suzuki, a player for the Orix Bluewave at the time, and recorded 3 strikeouts in 3 at-bats with a walk. Matsuzaka states that this game was the moment he started to believe that he “belonged” in pro baseball. However, Ichiro would get a bit of revenge on Matsuzaka by hitting his 100th career home run off him in July of that year.

Matsuzaka started in the All-Star game as a rookie in 1999. He struck out Takuro Ishii and Takanori Suzuki of the Bay Stars before number three hitter Yoshinobu Takahashi of the Giants managed to make contact and fly out to left field.

In his first professional season in 1999, Matsuzaka had 16 wins and 5 losses as the team ace, and was voted Rookie of the Year. Another rookie pitcher in the rival Central League, Koji Uehara, also won the same honor with a 20-win season. Together, they would come to represent their respective leagues as dominant starting pitchers for seasons to come.

He was selected for the NPB All-Star Game in 1999, 2000, 2001, 2004, 2005, 2006. He was voted MVP of the 2004 game.

In 2000, Matsuzaka had 14 wins and 7 losses. He had 15 wins and 15 losses in his 2001 season and won the Eiji Sawamura Award.

Matsuzaka became involved in a scandal when he began dating Shibata. On September 13, 2000, he drove to her apartment without a valid license. He illegally parked his car and it got towed, and then had a team official take the blame to avoid a scandal. The truth soon got out and he was fined 195,000 yen by the police and put under house arrest for one month by the Lions.

Matsuzaka spent a considerable portion of his 2002 season on the disabled list, which did not count toward his service time. He was not able to regain his pitching form in the 2002 Japan Series, when the Lions faced the Yomiuri Giants. In Game 1 at Tokyo Dome, where the designated hitter rule is not allowed, Matsuzaka batted 7th in the lineup to take advantage of his above-average hitting for a pitcher. However, not only did Matsuzaka not fare well at the plate in this game, but he also helped the Giants to a rout by giving up two key home runs. One was to extremely popular Giants first baseman Kazuhiro Kiyohara, who hit a middle-of-the-plate Matsuzaka fastball off one of the billboards at the back of the left field stands (That footage can be seen in the external links section). Matsuzaka would give up another key RBI to Kiyohara in game 4 in relief, as the Lions were meekly swept by the Giants in the series.

In 2003, Matsuzaka logged 16 wins and 7 losses. He easily won the Pacific League ERA title with a 2.83 mark. Matsuzaka used to play for Japan’s National Baseball Team, and pitched against South Korea.

He participated in the 2004 Olympic Games in Athens, Greece. However, he lost the semifinal game to Australia by the score of 1–0. His team later defeated Canada, earning the bronze medal for Japan.

Matsuzaka is married to television journalist Tomoyo Shibata, formerly of Nippon TV in Japan, and in 2005 she gave birth to the couple’s daughter. He also has a son, born on March 15, 2008.

On October 25, 2006, Scott Boras was announced as Matsuzaka’s agent to represent him in any contract dealings in the Major Leagues. On November 2, Matsuzaka was officially granted permission by the Lions to pursue a career in Major League Baseball via the posting system.

In 2006, Matsuzaka pitched for Japan in the inaugural World Baseball Classic. He was crowned the MVP of the first World Baseball Classic after Team Japan defeated Team Cuba 10–6 in the finals. Matsuzaka, the winner of the finale, threw 4 innings of 1 run baseball before exiting. Overall, Matsuzaka pitched a total of 13 innings throughout the tournament while finishing with 3 wins and no losses. There had been talk of Matsuzaka wanting to go to Major League Baseball before the ’06 WBC, and the tournament allowed Matsuzaka to show his skills on the worldwide stage. Interest in Matsuzaka from MLB teams boomed after his performance throughout the WBC.

Matsuzaka was an accomplished hitter in high school and he got his first hit in his first career at-bat, a single to center, in a game against the Orix Blue Wave when the Lions ran out of bench players and had to allow him to hit for himself. The Pacific League employs the designated hitter rule. Matsuzaka’s first pro home run came in an interleague game against Hanshin Tigers pitcher Darwin Cubillán at spacious Koshien Stadium on June 9, 2006. That footage can be seen in the external links section.

On December 13, Matsuzaka and Boras joined Red Sox GM Theo Epstein, CEO Larry Lucchino, and Chairman Tom Werner on a private plane owned by Red Sox owner John Henry headed for Boston. During the flight—which was followed by both the Boston and the Japanese media—the group agreed to terms on a contract. Journalist Nobuhiro Chiba characterized Japanese reaction to the signing: “I think the people are relieved to send Daisuke to the Boston Red Sox.” In Boston, Matsuzaka passed his physical and signed a six-year, $52 million contract, which could have been worth as much as $60 million if he fulfilled incentives. The details of the contract included a $2 million signing bonus with a $6 million salary in 2007, $8 million in each of the following three seasons (2008–2010), and $10 million in each of the final two years (2011–2012). He also had a no-trade clause, specially constructed by the Red Sox to fit Matsuzaka’s contract.

Matsuzaka made his first major league regular season start for the Red Sox on April 5, 2007, in an afternoon game against the Kansas City Royals at Kauffman Stadium. He walked one, recorded 10 strikeouts, and at one point retired 10 consecutive batters. He allowed only a solo home run on 6 hits while throwing 108 pitches (74 for strikes) over 7 innings and recorded the win as the Red Sox triumphed by a score of 4–1. He was, however, beaten 3–0 by Félix Hernández (who pitched a one hitter), Ichiro Suzuki, Kenji Johjima, and their Seattle Mariners in his Fenway Park debut on April 11, 2007 and defeated again, 2–1, by the Toronto Blue Jays in his third major league start despite striking out 10 Toronto hitters in only 6 innings. Matsuzaka still became the only pitcher to strike out 10 or more batters in 2 of his first 3 big-league starts since Fernando Valenzuela did so in 1981.

Matsuzaka pitched his first complete game in the major leagues on May 14, 2007, a 7–1 victory over the Detroit Tigers. He had pitched 72 complete games in Japan.

On September 28, 2007 Matsuzaka went eight innings and threw 119 pitches. He allowed six hits and two runs while striking out eight. With the win against the Minnesota Twins to secure the Red Sox’s place as the winner of the Division, he closed out his first Major League season with a record of 15–12 and an ERA of 4.40.

On October 6, 2007, Matsuzaka made his Major League playoff debut in the 2007 ALDS, in front of his home crowd in Boston against the visiting Los Angeles Angels. Matsuzaka started the game but lasted just 4 and 2/3 innings, giving up 3 earned runs on 7 hits before being pulled. Although Matsuzaka did not get the decision, the Red Sox eventually beat the Angels 6–3.

On October 15, 2007, Matsuzaka started in his second playoff game, in game 3 of the 2007 ALCS against the Cleveland Indians in Cleveland. Much like his playoff debut, Matsuzaka delivered another mediocre outing. Again, Matsuzaka was not able to make it past 5 innings, lasting 4 and 2/3 innings, giving up 4 earned runs on 6 hits. Matsuzaka was pulled after going over the 100-pitch mark. Matsuzaka suffered his first career playoff loss as the Indians beat the Red Sox 4–2. Matsuzaka fared better in Game 7 of the series, on October 21, 2007, retiring the first eight batters he faced. Matsuzaka pitched well for 5 innings, allowing 2 runs. The Red Sox won 11–2, to advance to the 2007 World Series against the Colorado Rockies. Matsuzaka is the first Japanese pitcher to win an MLB playoff game and only the fifth rookie to start a game seven in the playoffs.

On October 27, 2007, he started and led the Red Sox to a 10–5 win in Game 3 of the 2007 World Series against the Rockies, his first World Series appearance, giving up 2 runs on 3 hits and 3 walks, with 5 strikeouts. In the game, he also recorded his first major league hit: a two-out 2-run single off Josh Fogg, making Matsuzaka the third pitcher in Red Sox history to record two RBIs in a World Series game; the others were Babe Ruth (in Game 4 of the 1918 World Series) and Cy Young. Matsuzaka is also the first Japanese pitcher in World Series history to start and win a game. The next day, the Red Sox won the Series in Game 4. With 201 strikeouts, Matsuzaka ended the year with the Red Sox rookie record for strikeouts in a season.

Matsuzaka ended the season with an 18–3 record, 2.90 ERA and held opponents to a .211 batting average (and 6.9 hits-per-9-innings), the lowest in the majors. He also led the AL by leaving 80.6 percent of the baserunners he allowed stranded. These numbers were enough to place him 4th in the American League Cy Young Award race. However, a major problem for Matsuzaka was the control of his pitches, which, combined with his lack of innings pitched due to his injury, factored into his Cy Young voting. He walked 94 batters in 167 and 2/3 innings (a major-league-leading 13.1% of all batters he faced), even walking an eye-popping eight in one game against the Detroit Tigers on May 5. Eight times in the 2008 season, Matsuzaka surrendered walks to five or more batters in a game, and 12 times he walked three or more in a game. The interesting statistic is that Matsuzaka was 11–1 in the 16 starts he walked three or more batters, which was a testament to his ability to wiggle out of whatever trouble he got himself into.

When Matsuzaka decided to pitch in the 2009 World Baseball Classic, the Red Sox were concerned with his decision being that it would cause him to miss a majority of spring training. Red Sox manager Terry Francona asked Team Japan manager Tatsunori Hara to keep him updated on Matsuzaka’s condition along with limiting Matsuzaka’s pitch count. Throughout the WBC, the Red Sox had limited access to Matsuzaka and decided not to press the issue more with Hara. Matsuzaka went on to lead Team Japan to victory earning the MVP award with a 3–0 record and 2.45 ERA.

On March 27, 2009, Matsuzaka reported to Red Sox spring training only twelve days before opening day. In Matsuzaka’s first start of the regular season, he gave up three home runs against the Tampa Bay Rays, ultimately losing the game. In his next game against the Oakland Athletics, Matsuzaka only lasted one inning, giving up five hits, five runs, two walks, and striking out none. Matsuzaka was quickly placed on the DL, while reliever Justin Masterson took his spot in the rotation.

Matsuzaka made his next start on May 22, 2009, against the New York Mets after being activated off the DL. He gave up five runs over five innings, receiving another loss. Matsuzaka gained his first win of the season against the Detroit Tigers on June 2, 2009, but failed to produce any quality starts. After a loss against the Atlanta Braves on June 19, 2009, Matsuzaka was once again placed on the disabled list. Red Sox manager Terry Francona stated that Matsuzaka was placed on the DL due to “weakness” in his throwing arm possibly caused by the extensive pitching he did in the World Baseball Classic. Francona also made it clear that it would not be a “two-week DL” stating “We’re going to have to figure this out. We have a lot of work ahead of us trying to get him back to being Daisuke.”

As of his second placement on the DL in the 2009 season, Matsuzaka held a 1–5 record with an 8.23 ERA. With Matsuzaka’s placement on the DL, it left a spot open in the starting rotation for John Smoltz to pitch in after being activated off the DL.

Although it has been suggested that the high number of innings pitched early in his career combined with a vigorous personal training regimen is a possible cause of Matsuzaka’s sustained injury problems in 2009, Matsuzaka himself has stated publicly that he feels he cannot maintain arm strength without extensive training.

On September 15, 2009, Matsuzaka made his first start since June 19. He came and pitched his best outing of the season, pitching six plus shut out innings, striking out five, walking three, and giving up three hits. In October 2009, Matsuzaka revealed that he had in fact injured his hip joint but did not reveal when he got the injury.

Matsuzaka also apologized to Red Sox fans, saying, “I am very sorry for making you worry. I assure you that the [2010] season will be a great season. I am going to redeem what I lost in 2009. With my health back, I am confident and determined to produce this year. I will [try my best to] become a world champion once again.”

Matsuzaka missed the first month of the season due to a neck strain. He returned on May 1 against the Orioles and gave up seven runs, six earned, and seven hits in 4 2/3 innings. Matsuzaka would improve during the season in 2010, going 9-6 with a 4.69 ERA in 25 starts, but fell well below expectations in terms of consistency and efficiency.

Matsuzaka had his first hit with the Red Sox on May 23, 2010, in Philadelphia. He also was tremendous in the post-season with his bat. He drove in two runs with a single in Game 3 of the 2007 World Series, during a six-run third inning, powering the Red Sox to a victory.

On May 5, 2011, Matsuzaka made his first relief appearance of his MLB career picking up the loss in 1 inning against the Los Angeles Angels of Anaheim after a 2 and a half-hour rain delay. On May 17, 2011, Matsuzaka was placed on the 15 Day disabled list. On June 2, it was reported that he would be out for the rest of the season due to Tommy John surgery. On June 10, Matsuzaka underwent the surgery.

On April 23, 2012, Matsuzaka made his first rehab start for the Single-A Salem Red Sox. He gave up a home run in each of his first two innings, and gave up three earned runs in four innings against the Wilmington Blue Rocks, an affiliate of the Kansas City Royals. After stints with both the Portland Sea Dogs and Pawtucket Red Sox, Matsuzaka was activated to make his first major league start of the season on June 9 in Fenway Park against the Washington Nationals, where he allowed 4 earned runs in 5 innings. He would finish the year with a very unimpressive record of 1-7 with an 8.28 ERA in 11 starts before becoming a free agent.

On February 10, 2013, Matsuzaka agreed to a minor league deal with the Cleveland Indians, reuniting him with former Red Sox manager Terry Francona. He did not make the Indians’ Opening Day roster, and was subsequently released from his contract, only to sign another minor league deal in March. Matsuzaka was released from the Indians’ organization per his request on August 20.

On August 22, 2013, Matsuzaka agreed to a major league deal with the New York Mets, and joined their starting rotation. During his stint with the Mets in 2013, Matsuzaka posted a 3–3 record with an ERA of 4.42.

Matsuzaka agreed to a one-year minor league contract to stay with the Mets for the 2014 season on January 24, 2014. On April 16, 2014, Matsuzaka had his minor league contract purchased by the Mets, replacing pitcher John Lannan on the 40-man roster. On April 24, Matsuzaka earned his second career save (first was in Japan in 2000) in a 4-1 victory over the St. Louis Cardinals. After the game, Mets manager Terry Collins stated that Matsuzaka was the back up option to current closer Kyle Farnsworth. On May 14, Farnsworth was outrighted to Triple-A by the Mets, leaving the closer role up for grabs, and Matsuzaka as one of the candidates for the job. On May 25, Matsuzaka was given his first start as a Met after 14 relief appearances. In his start, Matsuzaka went 6 innings and gave up only 2 earned runs on only 3 hits and got the win in a 4-2 victory over the Arizona Diamondbacks.

Matsuzaka signed a contract with the SoftBank Hawks on December 5, 2014, rejoining Nippon Professional Baseball after eight years in Major League Baseball. Hampered by injuries, Matsuzaka pitched in just one game for the Hawks’ farm team in 2015. In 2016, Matsuzaka appeared in his first NPB game in 10 years. He pitched one inning for the Hawks and allowed two earned runs.

Matsuzaka was able to pitch only one game in three years for the Fukuoka SoftBank Hawks. On November 5, 2017, the Hawks released Matsuzaka.

On January 23, 2018, Matsuzaka signed with the Chunichi Dragons. On April 5, Matsuzaka started his first game in Japan in 12 years against the Yomiuri Giants, pitching five innings and allowing three earned runs in a 3–2 loss. He was selected for the 2018 NPB All-Star game. After the season, he was awarded “The Best Comeback Prize” of NPB for his 6–4 record.

On 4 October 2019, Matsuzaka left the Dragons after failing to agree to a new deal.

On December 3, 2019, Matsuzaka signed a one-year contract to return to the Lions.