Playing in the Texas League in 2011, Adams was recognized as that league's Most Valuable Player and the Cardinals Minor League Player of the Year with a .300 batting average, 32 home runs and 101 runs batted in. He made his MLB debut with the Cardinals in 2012. In his rookie season in 2013, Adams hit 17 home runs in 296 at-bats.
Matt Adams grew up in Philipsburg, Centre County, Pennsylvania. According to an interview with Fox Sports Midwest he was a big fan of Ken Griffey, Jr. After graduating from Philipsburg-Osceola High School he attended Slippery Rock University where he holds the career records of batting average (.473) and slugging percentage (.754). In 2009, he was named the National Collegiate Baseball Writers Association's Division II National Player of the Year.
The St. Louis Cardinals drafted Matt Adams in the 23rd round of the 2009 Major League Baseball draft. At each level he played in the minor leagues, Adams displayed prodigious hitting ability. His first full-season assignment came in 2010 with the Quad Cities River Bandits of the Class A Midwest League. In 121 games, he batted .310 with 71 runs scored, 44 doubles, 22 home runs (HR), and 88 runs batted in (RBI). His .541 slugging percentage (SLG) led all Cardinals minor leaguers.
In 2011, Adams was named the Cardinals Minor League Player of the Year and the Texas League Most Valuable Player (MVP) after hitting .300, a .357 on-base percentage (OBP) and .566 SLG with 32 HR and 101 RBI in 115 games. He set club records in home runs and RBI, including eclipsing the mark of 29 HR Colby Rasmus set in 2007. After the season, Adams played in the Arizona Fall League (AFL), and he was selected to represent the Cardinals in the AFL Rising Stars Game.
Prior to the 2012 season, Baseball America considered him the ninth best prospect in the Cardinals organization. On May 20, 2012, the Cardinals called Adams up after placing Lance Berkman on the disabled list (DL). He went 2-for-4 in his major league debut. He hit his first major league home run six days later. Adams played in 27 games with the Cardinals where he hit .244 with 13 RBI and two home runs before returning to Memphis.
Splitting time between the Memphis Redbirds of the Class AAA Pacific Coast League and the Cardinals, he continued to show consistent power and batting average in the minor leagues. At Memphis, Adams hit 18 home runs with 50 RBI as he batted .329 with a .624 slugging percentage. However, an elbow injury brought an early end to his 2012 season. 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.
Adams led the Cardinals in 2013 spring training with 17 RBI. It was at that point that Adams earned his nickname, "Big City." 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." Said Freese: "Well he's a big boy that can rake [the ball]. I guess it hit because the guy can flat-out hit." 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. For a significant part of April, his batting average hovered between .640 and .700.
With a right oblique strain, the Cardinals placed Adams on the 15-day disabled list on April 26, retroactive to April 22. As the season progressed, teams began to notice his pull-hitting tendencies and often employed an extreme infield shift on him that left one or no fielders on the left side of the second base bag. He also had difficulty hitting off-speed pitches from left-handed pitchers. Because he often grounded out to the right side of the bag, his batting average began to precipitously decline. In June, he batted just .179 and .205 in August.
At the conclusion of his rookie season, Adams finished with a .284 batting average and .503 SLG. He connected for 17 HR in 296 AB for a ratio of one home run every 17.41 at bats. That represented the third-best figure for rookies in franchise history. His home run to fly ball ratio was 21.8%, ranking 11th in the major leagues for all players with at least 300 PA. Regular right fielder Carlos Beltrán became a free agent after the season. Craig shifted to right field to replace him, clearing a way for Adams to assume first base regularly.
During a game against the Cincinnati Reds on April 3, 2014 in Cincinnati, Adams was attempting to catch a Chris Heisey pop-up that sailed into the shallow part of the seats. The infield tarp was in Adams' run path. As he leaned over the tarp to catch the ball, it was falling toward the second row of seats, and a fan named Chris Smith caught the ball with his own glove just above Adams' outstretch glove. 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. Smith, who had been recovering from knee surgery, gestured an obscenity with his hand toward him. 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.
Opponents escalated the rate of infield shifting the employed against Adams in 2014, as it was already a league-wide trend. 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. 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. The results of his modified approach began to show, as he was batting .357 with a .400 OBP and .548 SLG through that game. Despite the drop-off in the power numbers, he continued to hit well against the shift. As of June 10, he was batting .390 (16 for 41) on ground balls and line drives against the shift with three home runs for the year. He also did it without successfully bunting for a base hit.
The team placed Adams on the DL for the second time in his MLB career from May–June. After his return, he homered in the first three games. 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. This was Adams' third MLB multi-home run game and first the six-RBI game for the Cardinals since David Freese did it June 7, 2012 against the Houston Astros. 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.
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. The home run accounted for the winning runs in the Cardinals' 3–2 victory, helping to secure their fourth straight NLCS appearance.
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. The Cardinals reactivated him on September 9. As an arbitration-eligible player prior to the 2016 season, Adams and the Cardinals agreed to a one-year, $1.65 million contract. He continued his success in foiling the shift through May 2016 by a slight modification to his swing, and as a result, successfully gaining hits to each of the three outfield zones over 30 percent of the time. He had hit .354, three home runs, 14 RBI and .604 SLG through the first 25 days of that month.
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. It was the second time in his career he had hit a walk-off home run in the 16th inning.
On May 20, 2017, the Cardinals traded Adams and cash considerations to the Atlanta Braves in exchange for minor league infielder Juan Yepez.