He has played in Major League Baseball (MLB) for the Atlanta Braves, Pittsburgh Pirates, Baltimore Orioles and Washington Nationals.

[13] As a result of an injury to starting center fielder Chris Duffy, McLouth received a substantial amount of playing time through the end of the season.

[16] McLouth entered spring training 2008 in a competition with teammate Nyjer Morgan for the starting job as the team's center fielder.

[20] McLouth was selected as a reserve to represent the Pirates in the 2008 MLB All-Star Game,[21] and was among the league leaders in various offensive categories.

He also made a clutch throw from center field in the 10th inning to catcher Russell Martin for an out at the plate that cut down Dioner Navarro, the potential game-winning run for the American League.

[22] In his final at-bat, with the game tied, McLouth hit a long fly ball that was caught on the right field warning track.

[26] After playing 45 games with the Pirates to start the 2009 season, McLouth was traded to the Atlanta Braves for prospects Jeff Locke, Charlie Morton and Gorkys Hernández on June 3, 2009.

[31] McLouth suffered a toe injury and missed a game on June 7 after colliding with the outfield wall at Dodger Stadium.

[32] Four days later, he was placed on the disabled list after reporting concussion-like symptoms as a result of a collision with right fielder Jason Heyward.

[41] Despite the rocky season, McLouth made the Braves playoff roster,[42][43] and was projected to start in left field against the San Francisco Giants in the National League Division Series.

Feeling significant discomfort in his left oblique, McLouth was placed on the 15-day disabled list on May 23 and replaced on the roster by Jordan Schafer.

[46] McLouth hit a solo home run on July 17 in the bottom of the eighth inning against the Washington Nationals to tie the game at eight.

[53][54] McLouth lined a walk-off single in the ninth inning to score Manny Machado, to defeat the Tampa Bay Rays on September 12.

[55] McLouth finished the season with a .268/.342/.435 batting line with 7 home runs, 18 RBI and 12 stolen bases in 236 plate appearances for the Orioles.

[56] In the Orioles' 5–1 victory over the Rangers in the first ever AL Wild Card Playoff Game, McLouth went 1-for-4 with two RBI, a stolen base and a run scored.

[59] McLouth hit the 100th home run of his career on September 24, 2013, off Toronto Blue Jays pitcher Todd Redmond.

[69] McLouth married Lindsay Rolen in February 2009.They, their two sons and two dogs live in Knoxville, Tennessee during the offseason.