Prior to his MLB career, Sweeney played football at the University of Maine. While in college he switched to playing baseball full time. He was originally drafted on June 4, 1990, by the Los Angeles Dodgers, but did not sign.

Sweeney was drafted again the following year, this time signing with the then named California Angels on June 5, 1991. He joined the Angels' minor league affiliates in 1992, where he played for his first few seasons.

Sweeney was traded on July 9, 1995 to the St. Louis Cardinals. On August 4, 1995, Sweeney was called up to make his MLB debut with the Cardinals. He continued to split his time between the major and minors over the next two years.

On June 13, 1997, Sweeney was traded to the San Diego Padres, where he finished the 1997 season and played in 1998. Sweeney played in the 1998 World Series with the Padres, which they lost to the New York Yankees. He was again traded on February 2, 1999, to the Cincinnati Reds.

The following year, he was traded to the Milwaukee Brewers on January 14, 2000. He continued with the Brewers until January 21, 2002, when they traded him to the New York Mets. Sweeney was released just short of two months later and signed with the San Diego Padres on March 16, 2002. Exactly six months later he was released by the Padres.

On January 24, 2003, he signed with the Colorado Rockies, where he stayed for the following two seasons. On December 22, 2004, he returned to the San Diego Padres, where he played for the 2005 season.

Sweeney signed as a free agent with the San Francisco Giants on December 8, 2005. On August 9, 2007, Sweeney was traded to the Los Angeles Dodgers, where he is on the full roster for the 2008 season.

1. Full name: Mark Patrick Sweeney
2. Born: October 26, 1969
3. Birthplace: Framingham, Massachusetts
4. Made MLB debut with the St. Louis Cardinals
5. 1997: Led his High School to the State Championships
6. 2007: Blamed by Barry Bonds on a positive amphetamine test result