He played in MLB for the Arizona Diamondbacks, Chicago White Sox, Baltimore Orioles, and Washington Nationals.

[2] In 1998, Cintrón spent the season with Rookie-League Lethbridge and hit .264 with 11 doubles, four triples, three home runs and 34 RBI in 67 games.

[2] Cintrón hit .307 with 25 doubles, four triples, three home runs and 64 RBI in 128 games with the Class-A Advanced High Desert Mavericks during the 1999 season.

Cintrón played in 125 games for the Double-A El Paso Diablos and hit .301 with 30 doubles, six triples, four home runs and 59 RBIs in 2000.

In 2001, Cintrón hit .292 with 24 doubles, three triples, three home runs and 35 RBIs in 107 games for the Triple-A Tucson Sidewinders.

[14] Cintrón continued his success into 2004, where he led the Diamondbacks in games played (154) and at-bats (564) and finished second in doubles (31) and third in hits (148).

Cintrón became the first player in franchise history to hit a home run from both sides of the plate on July 8 against the San Francisco Giants, hitting a solo home run off Dustin Hermanson in the fourth inning and a three-run shot off Wayne Franklin in the seventh, finishing with a career-high 4 RBI.

Cintrón hit two triples on April 13 against the Detroit Tigers, the first Sox player to accomplish the feat since José Valentín in 2004.

[19] Cintrón signed a minor league contract with an invitation to spring training with the Chicago Cubs on February 18, 2008.

[22] After starting the season with the Norfolk Tides, his contract was purchased by the Orioles, and he was added to the active roster on May 11.

[34] On May 24, 2011, Padres minor league broadcaster Tim Hagerty announced through Twitter that Cintrón had retired.

[36][37] In early 2012, Cintrón came out of retirement to play for the Sugar Land Skeeters of the Atlantic League of Professional Baseball.

[38] Cintrón was Manager of the Azucareros de Yabucoa (his hometown) in Puerto Rico's Superior Baseball League (Double A Category).[when?]

The Houston Astros hired Cintrón as the club's Spanish-language interpreter, advance scout, and assistant coach for the 2017 season.

[41] Cintrón was announced as the first manager of RA12 before their inaugural 2020–21 season but withdrew from the team in late October due to health concerns.

In the pivotal Game 6, Cintron and fellow hitting coach Troy Snitker noticed that Yordan Alvarez had a hitch in his swing (namely due to his weight being shifted in his front leg) that merited adjustment.

Cintron looked at video from a few months ago and saw that Alvarez's hands had dropped in his stance from June, which made it harder to deal with a fastball.

While the Blue Jays had still yet to finalize their decision, it was announced on November 21, 2022, that the Astros signed Cintrón to a contract to remain through the 2025 season.