He has previously played in Major League Baseball (MLB) for the St. Louis Cardinals, New York Yankees, and San Diego Padres.

A three-time second-team All Mountain West Conference selectee, he broke TCU's school record for games played and at bats and is second in hits, doubles and walks.

A three-time MLB All-Star Game selection, he became the first Silver Slugger Award winner at second base in Cardinals franchise history after leading the major leagues in hits, runs scored and doubles in 2013.

[5] At Elkins High School, Carpenter was a three-year first-team all-district performer and two-time all-state tournament team selection.

[11] He spent his first professional season with various A-level teams, including the Batavia Muckdogs, Quad Cities River Bandits, and the Palm Beach Cardinals Between the three clubs, he batted .283 with two home runs and 22 RBIs.

[12] After his 2010 performance, Carpenter started to garner attention, and was expected to compete for one of the MLB Cardinals final roster openings the next spring training.

[16] After the 2011 season, the departures of Albert Pujols and Nick Punto — along with an injury to Allen Craig — opened up an opportunity for Carpenter to make the major league club.

Carpenter hit his first career postseason home run on October 17, 2012, during Game 3 of the National League Championship Series (NLCS) against the San Francisco Giants.

Uncertain of where the club would find adequate offensive production from second base, the Cardinals advised Carpenter to work out there in the off-season prior to 2013.

Manager Mike Matheny moved Carpenter into the leadoff spot midway through April in spite of him lacking the speed sought after for that post in the lineup.

[22] He also finished in the top ten in the NL in batting average, on-base percentage (.392), total bases (301), singles (126), triples (seven), walks (72), and adjusted OPS (143), among others.

In the fourth inning of Game 6, Carpenter faced Dodgers ace Clayton Kershaw and lined a double to right field to end an 11-pitch at bat and ignite a four-run outburst.

[35] In a June 4 matchup against the Kansas City Royals, Carpenter raked five hits in five at-bats to raise his batting average to a season-high .307.

[37] After first-half results through July 6 including a .282 batting average, four home runs, 32 RBI, and a .375 OBP, he was selected to his second All-Star Game at Target Field in Minneapolis, Minnesota.

In the following at bat opposing Kershaw in the seventh inning, he found himself in an 0–2 count, but battled eight pitches for a bases-clearing double that gave the Cardinals a 7–6 lead.

Further, the seven consecutive multi-hit games with at least one extra base hit in each tied the Cardinals' franchise record which Ripper Collins originally set in 1935.

He ripped his second leadoff home run of the season against Washington on April 22,[51] and the next day he lined the first pitch of the game off Max Scherzer for a double.

[55] He was withheld from a weekend series against Pittsburgh May 8–10 due to "extreme fatigue",[56] after team physicians diagnosed dehydration and an accelerated heart rate.

[68] On May 19, he established a new career-high six RBI in a game at Busch Stadium against the Colorado Rockies, with two doubles and his ninth home run of the season in 13–7 win.

[73] After leading the NL in OPS (1.008) for the first half of the season, Carpenter was selected as a reserve on July 5 for the All-Star Game at Petco Park in San Diego.

He served a one-game suspension on April 25 of a series opener versus the Toronto Blue Jays for having bumped umpire John Tumpane two days prior, when he had been ejected for arguing a pair of called strikes in the seventh inning.

[82] In the aftermath of Hurricane Harvey flooding Greater Houston in late August, Carpenter announced that he would donate $10,000 to relief efforts for every homer he hit for the rest of the season.

However as Matheny continued to utilize him in other spots in the batting order to attempt to increase the overall productivity of the Cardinals' lineup, the results were significantly inferior.

[91] Meanwhile his improved performance garnered nomination as one of five finalists for the NL Final Vote to play in the All-Star Game, which the Brewers' Jesús Aguilar won.

[95] During a matchup on July 20 at Wrigley Field versus the Chicago Cubs, Carpenter's three home runs and two doubles contributed to him tying or setting multiple records, while amassing all five hits and seven RBI within the first six innings of an 18−5 rout.

[91][96] On July 22, he was named NL Player of the Week after batting .529 with six home runs and a 1.706 slugging percentage during St. Louis' five-game set in Chicago.

[100] His resurgent performance gained national attention as an MVP candidate, having established himself as the league leader in doubles, home runs, slugging percentage, OPS, and Fangraphs WAR in early August.

[105][106] Over 564 at bats, the entire season elapsed with Carpenter having avoided grounding into a double play, making him the first Cardinal to achieve the feat with at least 550 at-bats.

That day, he tied his career high with seven RBI, while hitting two home runs with a double and a walk to lead a defeat of the Chicago Cubs, 18–4.

If you’re looking for some solid ground or some rock to hold onto, there’s only one way and that’s through Him.”[146] When Carpenter had elbow surgery at Texas Christian University, he stated that he leaned on his faith during that tough time.