Martinez was the 1st round draft pick for the Seattle Mariners in 1988 out of The University of Tampa where Tino starred during his time on campus. He began his major league career in 1990 and has played for the Mariners, New York Yankees, St. Louis Cardinals, and Tampa Bay Devil Rays, and rejoined the Yankees in the 2005 season, hoping to finish his career there.. During his career, he has scored over 900 runs, driven in over 1000 runs, and hit over 300 home runs. He has had 100 RBIs in six seasons and has been on the All-Star team twice.

Martinez spent the first part of his career with the Seattle Mariners. He had several mediocre seasons, but broke out in 1995 when he drove in 111 runs, hit 31 home runs and batted .293. The following season, he joined the Yankees. Replacing Yankee legend Don Mattingly, he had big shoes to fill, but he was ultimately embraced by the fans and became one of the franchise's most popular players.

Tino's most notable achievements in his career came when he helped lead the New York Yankees to World Series championships in 1996, 1998, 1999, and 2000. The four titles formed what is considered one of the great dynasties the game has ever seen. He also won the Home Run Derby in 1997.

Martinez hit two memorable home runs in as a Yankee in the World Series. The first came off of Mark Langston in Game 1 of the 1998 Series. The Yankees had tied the game earlier in the inning with a Chuck Knoblauch 3-run home run. The following three batters got on base, and Martinez came to the plate. After taking a very close ball 3, he hit a grand slam into the upper deck on a 3-2 count, giving the Yankees a four run lead. The second came on October 31, 2001. With two outs in the 9th inning and the Yankees trailing by two runs, Martinez came to the plate with a runner on. He hit a home run off of Arizona Diamondbacks closer Byung-Hyun Kim. The feat was repeated the following night by Scott Brosius, in one of the most amazing series of events in baseball history.

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 MVP voting. Ironically, this was the only season between 1996 and 2000 when the Yankees did not win the world series.

After the 2001 season, Tino went on to play for the St. Louis Cardinals for two seasons, replacing the aging legend Mark McGwire. He spent the 2004 season with the Tampa Bay Devil Rays. His production during these three years declined, and he went through several prolonged slumps.

Martinez returned for a second tour of duty with the Yankees in the 2005 season. From May 7, 2005 to May 11, 2005, Martinez hit 5 home runs in 5 straight games, which is one more than his previous record set from June 27, 2001 to July 1, 2001. While held homerless on May 12, 2005, Tino hit two homers on May 15 to give him 8 HR in 8 games. On November 8, 2005, the Yankees declined their $3 million option on Martinez, making him a free agent. On Wednesday February 15, 2006 Tino Martinez officially decided to end his playing career. Martinez confirmed the decision in the St. Petersburg Times, telling the paper that he will begin his broadcasting career at ESPN. Martinez said that the offer from ESPN made his decision to retire a lot easier, as he will work on "Baseball Tonight," do some radio work and cover a few games.

In 16 years, Martinez hit .271 with 339 home runs and 1,271 RBIs. During his seven years with the Yanks, he hit 192 homers and drove in 739 runs.

During the 2004 Summer Olympics Games held in Athens, Greece, when the host nation was lacking in baseball and softball players, they decided to put together teams of North American players of Greek heritage. Martinez, having some Greek in him, was approaced by team manager Rob Derksen and asked to play for the host nation. Unfortunately, Martinez, along with MLP Eric Karros and Aaron Miles (who was just recruited by the Colorado Rockies), were playing in the majors during that time and were not able to make the team.