Beer was a starter his freshman year at Clemson in 2016.[6] His first collegiate home run was a grand slam.[7] Against Boston College, he hit a 10th inning walk-off home run.[8] Beer was named the National Midseason Player of the Year by Perfect Game after hitting .430/.538/.935 with 13 home runs and 37 RBIs in 27 games.[9] He was awarded the Dick Howser Trophy for the national college player of the year for the 2016 season, the first time the award was given to a freshman.[10]
On July 31, 2019, the Astros traded Beer to the Arizona Diamondbacks along with prospects J.B. Bukauskas, Corbin Martin, and Joshua Rojas for Zack Greinke.[20] He was assigned to the Jackson Generals of the Southern League, finishing the season there. Over 122 games between Fayetteville, Corpus Christi, and Jackson, Beer batted .289/.388/.516 with 26 home runs, 31 hit by pitch, and 103 RBIs.[21] On July 7, 2020, it was announced that Beer had tested positive for COVID-19.[22] He did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.[23] Beer began the 2021 season with the Triple-A Reno Aces.[24]
On September 10, 2021, Beer was selected to the 40-man roster and promoted to the major leagues for the first time.[25] In his MLB debut that day, Beer homered against the Seattle Mariners' Diego Castillo, becoming the 129th player in MLB history to homer in his first major-league at-bat. On September 14, Beer suffered a dislocated left shoulder and was placed on the injured list three days later.[26]
In 2021, with Triple-A Reno, he batted .287/.398/.511 with 73 runs (2nd in the Triple-A West), 33 doubles (3rd), and 30 hit by pitch (leading the league) in 362 at bats.[27]
Beer hit a walk-off three-run homer to give the Diamondbacks a 4–2 Opening Day victory over the San Diego Padres on April 7, 2022, and he became the first rookie in Major League history to hit a walk-off home run while trailing on Opening Day, which was also coincidentally National Beer Day.[28] Beer was optioned to the minors on May 15.[29] In 38 games with Arizona in 2022, Beer hit just .189/.278/.243 with one home run and nine RBIs.
Beer was optioned to Triple-A Reno to begin the 2023 season.[30] In 19 games for Reno, he batted .200/.266/.314 with 2 home runs and 12 RBIs. Beer was designated for assignment on May 3, 2023, following the promotion of Brandon Pfaadt.[31] He cleared waivers and was sent outright to Triple-A Reno on May 9.[32]
Beer was a swimmer when he was younger, and, at 12 years old, he set national records in the 50-meter backstroke and 100-meter backstroke.[35][36] He later quit swimming to focus on baseball after two high school seasons. He also played two seasons of high school football.