[5] He was inducted into the William and Mary Athletic Hall of Fame in 2012 along with fellow alum and current Pittsburgh Steelers head coach Mike Tomlin.

Harris began his professional career in 2001 with the Single-A Lansing Lugnuts of the Midwest League, batting .274 with four home runs and 22 RBI in 32 games.

He hit .311 with eight home runs and 26 RBI in 56 games, leading to his first Major League call-up with the Cubs on July 3.

[11] On July 31, 2004, Harris was traded to the Montréal Expos as part of an eight-player, four-team trade that sent brought Nomar Garciaparra and Matt Murton to Chicago, Doug Mientkiewicz and Orlando Cabrera to the Boston Red Sox, minor leaguer Justin Jones to the Minnesota Twins and Harris, Francis Beltrán and Alex Gonzalez to Montreal.

[11] His home run, the first of his MLB career, was hit on September 15, off Josias Manzanillo of the Florida Marlins.

[11] On July 13, 2006, Harris was sent by Washington along with Gary Majewski, Bill Bray, Daryl Thompson, and Royce Clayton to the Cincinnati Reds in exchange for Felipe López, Austin Kearns, and Ryan Wagner.

[14] He played in 43 games with the Triple-A Louisville Bats in the International League, hitting .324 with five home runs and 28 RBI.

Harris also saw his first post-season action when the Twins faced the New York Yankees in the 2009 American League Division Series.

[18] Harris was the front-runner to start at third base for the Twins in 2010, but Nick Punto got the nod on Opening Day.

Punto was later replaced by rookie Danny Valencia and on June 24, Harris was outrighted to Triple-A Rochester after a 5–0 loss to the Milwaukee Brewers.

On December 9, 2010, the Baltimore Orioles acquired Harris in a trade along with J. J. Hardy for minor-league pitchers Brett Jacobson and Jim Hoey.

[7] Harris signed a minor league contract with the Los Angeles Dodgers on November 18, 2013, that included an invitation to spring training.

In November 2019, Harris was hired by x10 Capital, a private equity firm based in San Francisco, CA.