He played in Major League Baseball (MLB) for the Seattle Mariners, New York Yankees, St. Louis Cardinals, and Tampa Bay Devil Rays from 1990 through 2005.

[1] Formerly a third baseman, Martinez was the first round draft pick for the Seattle Mariners in 1988 out of the University of Tampa, where he starred during his time on campus.

His grandfather owned a small cigar factory, in which Martinez and his brothers, as well as childhood friend and fellow future major-leaguer Luis Gonzalez, worked as young boys.

Following that season, the New York Yankees acquired Martinez, along with Jeff Nelson and Jim Mecir, for Sterling Hitchcock and Russ Davis.

He hit a game-tying home run to right center off Arizona Diamondbacks closer Byung-hyun Kim, and the Yankees went on to win the game.

His best season statistically came in 1997, when he was second in the American League in home runs and RBI (with 44 and 141 respectively), and finished second in AL Most Valuable Player voting.

On May 19, 1998, he was hit by a pitch in the upper back by Baltimore Orioles pitcher Armando Benítez, which resulted in an intense brawl between the two teams.

The series went to Game 7, which Arizona won when Luis Gonzalez, Martinez's best friend, hit a game-winning single off Yankee closer Mariano Rivera in the bottom of the 9th inning.

The Yankee fans cheered him for a curtain call, a rare occurrence in honor of a visiting team's player.

Prior to the 2004 Summer Olympics, the host nation, Greece, trying to build up their chances of winning a medal, decided to put together a team of North American baseball players of Greek heritage.

Martinez, along with fellow MLB players Eric Karros and Aaron Miles, declined the offer because the games were in the midst of the Major League Baseball season.

[citation needed] On November 8, 2005, the Yankees declined their $3 million option on Martinez, making him a free agent.

[16] Starting in Spring training 2010, Martinez became a color commentator for the YES Network, replacing the departed David Cone.

[17] He made his regular season debut on April 9, 2010, when he called a game between the Yankees and the Rays that was coincidentally played back in his home area of Tampa Bay.

Martinez's behavior in the clubhouse was reported to include verbal attacks towards the Marlins' Justin Ruggiano and Chris Valaika, along with minor league player Matt Downs.

[19] In 2023, Martinez returned to the Cape Cod Baseball League as assistant coach of the Hyannis Harbor Hawks.

[citation needed] Martinez also participates annually in the Derek Jeter Celebrity Invitational (DJCI) golf tournament in Tampa.

[23] Martinez, who left the University of Tampa after his junior year to pursue professional baseball, received a bachelor's degree at UT in liberal studies on May 7, 2011.