He played in Major League Baseball (MLB) from 2000 to 2009 for the Detroit Tigers, Tampa Bay Devil Rays, Houston Astros, and Oakland Athletics.

Munson graduated from San Diego's Mount Carmel High School where he played baseball with former major league third baseman Eric Chavez.

Munson however did not sign, opting to play college baseball at the University of Southern California, where he was named Freshman All-American.

Despite playing the catcher position in high school and college, the Tigers had drafted Munson mostly for his hitting skills, and the decision was made to shift him to first base.

In 2002, while playing for the Toledo Mud Hens, Munson was named the Detroit Tigers Minor League Player of the Year.

On June 26, 2004, he hit what was then the longest home run in the history of Comerica Park off of Arizona Diamondbacks pitcher Brandon Villafuerte.

Munson soon thereafter signed with the Tampa Bay Devil Rays' Triple-A affiliate, the Durham Bulls, where he again played first base.

On August 20, 2006, Munson was designated for assignment by the Astros and he accepted a demotion to their Triple-A affiliate, the Round Rock Express, in the Pacific Coast League.

Due to the injury to Astros catcher Héctor Giménez, Munson was recalled to the major league roster on June 2, 2007.