Nicknamed "Big City" for his imposing size and ability to regularly hit long home runs, the St. Louis Cardinals selected Adams in the 23rd round of the 2009 MLB draft from Slippery Rock University of Pennsylvania.

He played in Major League Baseball (MLB) for the Cardinals, Atlanta Braves, Washington Nationals, and Colorado Rockies.

After graduating from Philipsburg-Osceola High School he attended Slippery Rock University[3] where he holds the career records of batting average (.473) and slugging percentage (.754).

The injury, which had been a nagging problem much of summer, finally had to be treated surgically in mid-August to remove a bone spur.

According to former teammate David Freese, several players had been searching for a nickname for the 6 ft 3 inch 230-pounder, when one day someone shouted out "Big City".

"[14] Adams started off the regular season on the St. Louis Cardinals roster as a bench player, backing up first baseman Allen Craig.

He caught the attention of the fans and media early on when in his first ten plate appearances he hit three home runs, two doubles, three singles, and a walk.

His home run to fly ball ratio was 21.8%, ranking 11th in the major leagues for all players with at least 300 PA.[18] Regular right fielder Carlos Beltrán became a free agent after the season.

Adams shifted his momentum to stand back up behind the tarp, and planted his glove on Smith's chest, pushing himself backward with a moderate shove.

During post-game interviews, Adams stated that he did not realize he had shoved Smith, but that he was preventing himself from falling into the stands.

To foil the shift, he began to hit the ball more to left field (also a technique known as "taking the pitch the other way") from the outset of the season.

[17] Another difference from the season prior was that he did not hit his first home run until the eleventh game of 2014, which took place against the Chicago Cubs.

[24] His first multi-homer game of the season came against the Colorado Rockies on June 23 at Coors Field with two home runs and six RBI in an 8–0 victory.

[26] In a July 7 contest against the Pittsburgh Pirates, Adams hit the first walk-off home run in the regular season by a Cardinals batter since Skip Schumaker did so against the Kansas City Royals in 2011.

[27] In Game 4 of the 2014 NLDS, Adams erased the Los Angeles Dodgers' 2–0 lead in the 7th inning with a three-run homer off ace Clayton Kershaw.

[28] On May 27, 2015, the Cardinals placed Adams on the DL with a torn quadriceps muscle, and he was initially supposed to miss the remainder of the season.

[30] As an arbitration-eligible player prior to the 2016 season, Adams and the Cardinals agreed to a one-year, $1.65 million contract.

[32] On July 22, 2016, while playing the Dodgers, Adams hit a 444 feet (135 m) home run in the 16th inning for walk-off, 4−3, win.

[33] On May 20, 2017, the Cardinals traded Adams and cash considerations to the Atlanta Braves in exchange for minor league infielder Juan Yepez.

[53] On April 21, 2022, Adams signed with the Kansas City Monarchs of the American Association of Professional Baseball.

[60] On January 17, 2025, the San Diego Padres hired Adams to serve as the bench coach for their Triple-A affiliate, the El Paso Chihuahuas.