In high school, in 2010 as a sophomore at the age of 16, Bregman became the first high school player to win the USA Baseball Player of the Year Award. In 2011 as a junior he batted .678, while setting a New Mexico season record with 19 home runs.
In three years of college baseball for Louisiana State University (LSU), Bregman was voted the 2013 National Freshman of the Year by Baseball America, won the 2013 Brooks Wallace Award, as the country's best college shortstop, and was a two-time All-American.
Towards the end of his junior year, he was selected by the Houston Astros with the second pick in the first round of the 2015 MLB draft. He was named a 2016 AA mid-season All Star, the 2016 USA Today Minor League Player of the Year, the MLB Pipeline 2016 Hitter of the Year, and the ESPN.com Prospect of the Year. The Astros called him up to the major leagues in July 2016.
Bregman is Jewish, and was born in Albuquerque, New Mexico. He was a member of Albuquerque's Congregation Albert growing up, and lived in Northeast Heights Albuquerque. His father Sam Bregman and his mother Jackie Bregman are both lawyers, and he has two younger siblings, Jessica and Anthony. His father played baseball as a freshman for the University of New Mexico Lobos in 1982, a team for which his uncle Ben Bregman also played; they both originally moved to Albuquerque to play baseball for the college on baseball scholarships. His father was also a part owner, starting in 2006, of the NBA Development League’s New Mexico Thunderbirds.
His grandfather Stan Bregman was the son of Russian Jewish immigrants. He was general counsel for the Washington Senators from the late 1960s until the team moved to Texas in 1971 in a sale that he negotiated, and he helped the club sign Hall of Famer Ted Williams as the team's general manager. His grandfather saw all of his games in high school. His great-grandfather Samuel "Bo" Bregman immigrated from Russia to Washington, D.C., around 1900, and married Sadie Hurwitz Bregman. He promoted boxing cards that featured, among others, Joe Louis, Billy Conn, and Bob Foster.
Bregman began playing tee-ball at age 4. In his first game, he turned an unassisted triple play by catching a line drive, tagging a runner, and then stepped on second base. He was a batboy for the University of New Mexico baseball team, and in 2004 served as a batboy for a game against Arizona State University and his then-favorite baseball player, Dustin Pedroia. Bregman attended Albuquerque Academy. His best friend is Blake Swihart, who plays for the Boston Red Sox, with whom he grew up playing travel ball.
Bregman was coached on travel baseball teams during his high school years at the Albuquerque Academy by Ryan Kellner and Jason Columbus, who in 2002 played for Louisiana State University (LSU) as a reserve first baseman. Bregman primarily played catcher.
In 2009, Bregman helped lead his high school team to a state championship as a freshman playing shortstop, batting leadoff in a lineup loaded with home run power for an average of .514 with three home runs, including one during the championship game that left Isotopes Park, the Dodgers' Class AAA team park. At the October 2010 COPABE Pan American Baseball Championships in Lagos de Mareno, Mexico, while he was a sophomore, he batted .564 for the gold-medal-winning 16-and-under USA National Team, and was named the MVP. That year, at the age of 16 he became the first high school player to win the USA Baseball Richard W. "Dick" Case Player of the Year Award.
In 2011, he batted .678 as a junior in high school, and established a season record in New Mexico with 19 home runs. Bregman was named first team All-State, and received All-Metro honors and All-District honors. In the fall of that year he led the 18-and-under U.S. National Team to a gold medal at the International Baseball Federation World Championships.
Bregman was originally projected to be a first-round draft pick out of high school. That changed, however, when he shattered the second knuckle on his right throwing hand in the fifth game of his high school senior season, while using his bare hand to deflect a bad hop on a ground ball. The injury made him miss most of his senior season. He was drafted by the Boston Red Sox in the 29th round of the 2012 Major League Baseball Draft as a second baseman, after he took the position that he would not sign with any team unless it picked him in the first round. He elected not to sign with the Red Sox. Instead, he chose to attend LSU.
At LSU, Bregman majored in sports administration. He also played shortstop for the LSU Tigers baseball team in the Southeastern Conference (SEC). He wore number 30 as a freshman, reflecting the 30 teams that had passed on him in the first round of the 2012 draft.
In 2013, he batted .369/.417/.546 with 104 hits (second in the nation), 18 doubles (third in the SEC), seven triples, six homers, 52 RBIs, 59 runs, and 16 steals in 17 attempts, and had a 23-game hitting streak. Bregman won the 2013 Brooks Wallace Award as the country's best college shortstop. He was also voted first-team All-American by Baseball America, the American Baseball Coaches Association (ABCA), Perfect Game, and the Jewish Sports Review. In addition, he was named the 2013 National Freshman of the Year by Baseball America, Collegiate Baseball, and the National Collegiate Baseball Writers Association (NCBWA), and was voted 2013 SEC Freshman of the Year and first-team all-SEC by the league coaches. Moreover, he was named 2013 ABCA First-Team All-South Region, National Collegiate Athletic Association (NCAA) Baton Rouge Regional Most Outstanding Player, Louisiana Freshman of the Year, and SEC Player of the Week (March 25, 2013), and named to the 2013 USA Collegiate National Team (for which he batted .361).
In 2014, he batted .316/.397/.455 with 16 doubles, 6 home runs, 35 runs, and 12 stolen bases. Bregman was voted 2014 second-team all-SEC, NCAA Regional All-Tournament Team, SEC All-Tournament Team, Second-Team All-Louisiana, and named to the 2014 USA Collegiate National Team.
In 2015, Bregman batted .312/.406/.534 with 22 doubles (tops in the SEC), 9 home runs, 49 RBIs, 37 stolen bases (leading the SEC, and the second-most steals in a season in LSU history), and 206 assists (leading the conference), led the nation's No. 1-ranked baseball team to the College World Series, and won LSU's Skip Bertman Award, which goes to the player who best exemplifies the spirit of the LSU Baseball program. He was also voted the Rawlings Gold Glove winner at shortstop by the ABCA, and voted first-team All-American by both Baseball America and the NCBWA for the second time, First Team D1Baseball, First Team Perfect Game, and Second Team Collegiate Baseball.
He was one of four finalists for the 2015 Golden Spikes Award, presented annually to the nation's top college player and won by outfielder Andrew Benintendi. Also, he was again a candidate for the Brooks Wallace Shortstop of the Year Award that he won in 2013.
In 190 career games at LSU, Bregman batted .338/.412/.520, with 66 strikeouts and 87 walks in 761 at bats.
Going into the draft, Bregman was lauded for his sense of the strike zone, bat speed, and ability to make frequent contact and strike out infrequently. He was also praised for his good range to both sides, first-step quickness, and instincts at shortstop, strong arm, good speed, and smart baserunning.
The Houston Astros selected Bregman with the second overall selection in the first round of the 2015 MLB Draft.</ref> He became the fifth LSU Tiger to be drafted in the first round in seven years, the highest-drafted position player in LSU's history, and the second-highest overall behind pitcher Ben McDonald (1989). He is the highest-ever-drafted player from New Mexico, ahead of 9th-picked pitchers Jim Kremmel (1971) and Duane Ward (1982), and the second-highest-ever drafted Jewish player, behind Ron Blomberg (1967).
TV analyst and former major league second baseman Harold Reynolds said he believed Bregman projected as a major league second baseman, rather than a shortstop. However, Bregman believes he can play shortstop in the majors, and said that every team that contacted him leading up to the draft had said the same. LSU head coach Paul Mainieri opined: "If you don’t think Alex Bregman can play shortstop at the Major League level, you don’t know the first thing about baseball." Mike Elias, the Astros' Director of Amateur Scouting, said Bregman would remain a shortstop, and that he thought Bregman would play shortstop through Houston's minor league system and into the major leagues. Similarly, Astros General Manager Jeff Luhnow said that there was "no question" that Bregman has the skills to play shortstop.
Bregman signed with the Astros in June 2015 for a $5.9 million signing bonus. He made his professional debut with the Quad Cities River Bandits of the Class A Midwest League in late June. In late July 2015, the Astros promoted Bregman to the Lancaster JetHawks of the Class A-Advanced California League.
Bregman started 2016 with the AA Corpus Christi Hooks in the Texas League, hitting .297 with 14 home runs and a .975 OPS, was named the league's Player of the Week on April 17, and was named a AA mid-season All-Star. In AAA with the Fresno Grizzlies, in 18 games he hit .333/.373/.641/1.015. Between the two teams, in 80 games he hit .306/.406/.580 with 20 home runs and 61 RBIs.
USA Today named Bregman the 2016 Minor League Player of the Year. Bregman was also named MLB Pipeline 2016 Hitter of the Year, and was selected as the third baseman for the MLB Pipeline 2016 Prospect Team of the Year. In addition, Bregman was named the 2016 Astros Minor League Player of the Year, ESPN.com Prospect of the Year, and a Baseball America Minor League All-Star.
On July 25, 2016, the Astros purchased Bregman's contract from the Grizzlies, adding him to their 25-man roster. He made his major league debut at third base against the New York Yankees that same day. He was the first position player from the 2015 Draft to debut in the Major Leagues. After he was hitless in his first 17 major league at bats through five games, the Astros moved him up to second in the batting order, to get him better pitches and demonstrate their confidence in him.
Bregman recorded his first major league hit on July 31 against the Detroit Tigers, with a single into center field. His first home run came at home on August 16, tying the game against the Cardinals in the first inning with a two-run home run to right field at Minute Maid Park. Bregman recorded his first major league grand slam on May 14, 2017 at Yankee Stadium, off of Masahiro Tanaka. The big hit capped a 6-run first inning, and the Astros won 10-7. For the 2016 season, he batted .264/.313/.478 with 8 home runs and 34 RBIs in 49 games, playing third base primarily. His slugging percentage was the seventh-best of any Astros rookie all-time.