He is perhaps best known for hitting a dramatic two-out, two-strike home run for the Tampa Bay Rays in the bottom of the ninth inning of the last game of the 2011 season, also known as Wild Card Wednesday.

[5] He struggled early in 2006, batting .237 before being demoted to the A's Triple-A Pacific Coast League affiliate, the Sacramento River Cats, in July.

[6] Johnson was expected to be the A's starting first baseman in 2007,[7] but suffered a torn labrum in his hip late in spring training and missed the first three weeks of the season.

[9] After the hot start, Johnson fell into a slump that lasted the rest of the season and plummeted his batting average to .236.

The Rays would not relinquish first place for the remainder of the season, and went on to win their first division title in franchise history en route to an American league pennant and an appearance in the World Series.

[11] Johnson signed a one-year contract for $1.2 million with the Yokohama Bay Stars of the Japanese Central League where he batted .215 in the 2009 season.

On April 8, 2011, with the Rays trailing 7–6 against the Chicago White Sox and two men on, Johnson hit the first pitch from Matt Thornton off the top of the Miller Lite Bullpen Sports Bar fence for a three-run home run, which would later prove to be the game-winner as Tampa Bay beat Chicago 9–7.

On September 28, 2011, with the Rays tied with the Boston Red Sox in the American League wild card race in the final game of the season, Johnson hit a pinch-hit home run with two outs and two strikes in the bottom of the ninth inning to tie the game against the New York Yankees.

[15] The Rays went on to win the game in extra innings, and coupled with a loss by the Red Sox, clinched the AL Wild Card.

[20] As background to this move Chicago sports writers recalled Johnson's home run in game 162 for the Tampa Bay Rays.

A season ago, Johnson changed baseball's landscape wrote Chicago Tribune writer, Phil Rogers.

On November 15, 2013, the Toronto Blue Jays announced that they had signed Johnson to a minor league contract with an invitation to spring training.

[26] His contract was selected from the Triple-A Buffalo Bisons on July 11, 2014, to replace Adam Lind who had been placed on the disabled list.

On July 26, Johnson recorded 4 RBI to help the Blue Jays end a 17-game losing streak at Yankee Stadium.

[32] After batting .158 over 19 at-bats in spring training, he was traded to the Cincinnati Reds for a player to be named later or cash considerations.

The club designated him for assignment on July 30 after trading for Brandon Moss, and outrighted Johnson off the 40-man roster to Memphis on August 3.

[36] On March 5, 2016, Johnson signed a minor league contract with the Tampa Bay Rays, with the intention to convert from a first baseman into a knuckleball pitcher.

[41] On May 15, 2017, Johnson signed with the Pericos de Puebla of the Mexican Baseball League, serving as both a designated hitter and a starting pitcher for the club.

Johnson put up big numbers for both clubs, finishing the season hitting .319 with 13 home runs and 57 RBIs in 62 games.