He played in Major League Baseball (MLB) for the Toronto Blue Jays, Chicago Cubs, Los Angeles Dodgers, Atlanta Braves, Miami Marlins, and Washington Nationals.

He recorded his first major league hit on April 20, 2003 against Boston Red Sox pitcher Casey Fossum and his first home run on May 17, 2003 against Jeremy Affeldt of the Kansas City Royals .

[3] He is one of only five batters, through August 2009, to have hit both a leadoff and walk-off home run in the same game (having done so in 2003), the others being Billy Hamilton (1893), Victor Power (1957), Darin Erstad (2000), and Ian Kinsler (2009).

[citation needed] In 2006, Johnson led all leadoff hitters in the American League with a .390 on-base percentage[5] and also had a .319 batting average.

The Blue Jays signed all-star shortstop David Eckstein, and removed Johnson from his familiar role as leadoff hitter.

Johnson "batted in" a game-winning run after he was hit by a pitch with the bases loaded on June 12, against the Atlanta Braves.

[9] During a crucial game in the 2008 season against the Milwaukee Brewers, Johnson executed a perfect hard slide into second base that prevented a double play, and allowed the Cubs to take a one-run lead.

On February 1, 2010, Johnson signed a one-year deal with the Los Angeles Dodgers to replace Juan Pierre as the team's fourth outfielder.

Johnson appears in the opening introduction sequence of The Tonight Show with Jay Leno as a Dodger player.

On January 12, 2011, Johnson signed a minor league contract to return to the Cubs organization that included an invitation to spring training.

[13] On April 20, Johnson hit a walk-off homer into the left-field seats off Luke Gregerson to defeat the San Diego Padres 2-1 in the first game of a doubleheader.

[14] Through 2011, he had the second-best career fielding percentage (.991) among all active major league left fielders, behind Ryan Braun.