Carter Kieboom Bio
Carter Alswinn Kieboom is an American professional baseball third baseman who is currently a free agent. He has previously played in Major League Baseball (MLB) for the Washington Nationals and Los Angeles Angels, and most recently played in the Philadelphia Phillies organization. Kieboom made his MLB debut in 2019 and was once considered one of the top prospects in the Washington Nationals farm system.
A graduate of George Walton Comprehensive High School in Marietta, Georgia, Kieboom committed to Clemson University before being selected in the first round of the 2016 MLB Draft. He is the brother of former Nationals catcher Spencer Kieboom, making the pair one of the few sibling tandems to reach the major leagues in recent years.
Early Life and Background
Carter Alswinn Kieboom was born on September 3, 1997, in Marietta, Georgia. He grew up in the Atlanta suburbs and attended George Walton Comprehensive High School, where he starred on the baseball diamond and developed into a top amateur prospect. His family background gave him an early connection to the game, as his father was born in the Netherlands and played baseball on the Dutch junior national team and in the Honkbal Hoofdklasse, the top baseball league in the Netherlands.
With baseball already woven into his upbringing, Kieboom quickly emerged as one of the most highly regarded high school infielders in the country. Following his senior season, he committed to Clemson University to play college baseball for the Clemson Tigers. That commitment, however, would be cut short when the Washington Nationals selected him in the first round of the 2016 MLB Draft.
Path to Baseball
Kieboom began his professional career in the summer of 2016 with the rookie-level Gulf Coast League Nationals after announcing he would sign with Washington on June 11. He batted .244 with four home runs and 25 runs batted in during his first taste of professional baseball, showing enough promise to move quickly through the system.
In 2017, Kieboom opened the year with the Single-A Hagerstown Suns, where he hit .333 with six home runs and 20 runs batted in before a hamstring injury in May placed him on the disabled list. He was named to the Northern Division All-Star team in the South Atlantic League and was listed by both Baseball America and MLB Pipeline as the Nationals’ fourth-best prospect during the season. After returning from the disabled list, he moved between the GCL Nationals, Low-A Auburn Doubledays, and Hagerstown, finishing the year with a .297 average and nine home runs across 61 games.
Kieboom’s ascent continued in 2018 with the High-A Potomac Nationals. He was selected to the Carolina League All-Star Game, where he went 3-for-5 and hit a home run. Following the All-Star break, he was promoted to the Double-A Harrisburg Senators and homered in his first game at the higher level against Baltimore Orioles prospect Keegan Akin. Later that summer, he represented Team USA as a member of Team World in the All-Star Futures Game at Nationals Park.
Carter Kieboom Career
Early Career (2016-2018)
Kieboom’s developmental years were marked by steady promotion and consistent offensive production. After a strong 2017 split between three levels, he returned to High-A Potomac in 2018 and quickly established himself as one of the more polished hitting infielders in the Nationals system. His Carolina League All-Star selection, combined with a successful Futures Game appearance, cemented his status as a rising star.
The 2018 season also saw Kieboom reach Double-A for the first time, giving Washington confidence that his bat could play at higher levels. By the end of that year, he was widely viewed as the third baseman of the future for the Nationals, setting the stage for a rapid rise through Triple-A in 2019.
Washington Nationals (2019-2021)
Kieboom began 2019 with the Triple-A Fresno Grizzlies in the Pacific Coast League. On April 26, 2019, the Nationals purchased his contract and promoted him to the major league roster for a series against the San Diego Padres. He made his debut that night and hit a home run for his first major league hit, an impressive start that hinted at his potential. He played 11 games with Washington that season, batting .128 with two home runs, while the Nationals went on to win the 2019 World Series over the Houston Astros, though Kieboom did not appear in any postseason action.
Following the departure of veteran third baseman Anthony Rendon after the 2019 season, manager Dave Martinez announced in January 2020 that Kieboom would move to third base full time and serve as Rendon’s permanent replacement. In the shortened 2020 season, Kieboom played 33 games and hit .202 with no home runs and nine runs batted in before a left wrist contusion ended his year early.
Kieboom’s most extensive major league action came in 2021, when he appeared in 62 games and hit .207 with six home runs. On March 20, 2022, it was announced that he would miss four to six weeks with a flexor mass strain near his right elbow, and on May 20, it was revealed he required Tommy John surgery, causing him to miss the entire 2022 season. He returned in 2023 and hit a home run in his first at-bat back in the majors, batting .207 with four home runs and 11 runs batted in across 26 games before being removed from the 40-man roster in March 2024 and sent outright to Triple-A Rochester. He played 91 games for the Red Wings, hitting .265 with seven home runs and 42 runs batted in, before electing free agency on November 4, 2024.
Los Angeles Angels (2025)
On December 6, 2024, Kieboom signed a minor league contract with the Los Angeles Angels and was assigned to the Triple-A Salt Lake Bees. He enjoyed a strong 2025 campaign in the Pacific Coast League, batting .319 with nine home runs, 57 runs batted in, and 11 stolen bases across 93 appearances. On September 16, the Angels added him to their active roster, and he went 2-for-8 with one run batted in during three big league appearances. On October 22, Kieboom was removed from the 40-man roster and sent outright to Salt Lake, after which he rejected the assignment and elected free agency.
Philadelphia Phillies (2026)
On January 13, 2026, Kieboom signed a minor league contract with the Cleveland Guardians. However, on March 21, he was traded to the Philadelphia Phillies in exchange for cash considerations, joining the Phillies organization as a depth option at the upper levels of the minor leagues.
Driving Style and Strengths
Kieboom has long been praised for his smooth left-handed swing and ability to work counts at the plate, drawing comparisons to a classic line-drive hitter. Defensively, he has experience at both shortstop and third base, providing positional flexibility, though Washington eventually settled on him as the everyday third baseman. His approach at the plate relies on pitch recognition and on-base skills rather than raw power, which made him an attractive prospect coming up through the minor leagues.
Notable Events and Milestones
Kieboom’s most memorable major league moment came on debut night in 2019, when he launched a home run for his first career hit against the San Diego Padres. He was also a member of the 2019 Nationals club that won the World Series, though he did not appear in any postseason games. Additional milestones include a 2018 Carolina League All-Star selection, an appearance in the All-Star Futures Game at Nationals Park, and a home run in his first at-bat upon returning to the majors in 2023.
Carter Kieboom Career Wins
Carter Kieboom’s professional resume is built more on prospect pedigree and positional versatility than on headline win totals. His career has been shaped by steady contributions at the minor league level, a strong 2025 season with Salt Lake, and several brief stints in the major leagues with Washington and Los Angeles.
Major League Highlights
In the majors, Kieboom has appeared in parts of four seasons with the Washington Nationals (2019, 2020, 2021, and 2023) and briefly with the 2025 Los Angeles Angels. His most productive major league season came in 2021, when he played 62 games and hit six home runs. He finished his Angels stint going 2-for-8 with one run batted in across three appearances.
Other Wins and Performances
Outside the majors, Kieboom’s strongest year came in 2025 with the Triple-A Salt Lake Bees, where he batted .319 with nine home runs, 57 runs batted in, and 11 stolen bases. He also earned Carolina League All-Star honors in 2018, was a South Atlantic League All-Star in 2017, and represented Team USA in the 2018 All-Star Futures Game.
Carter Kieboom Family
Family Background and Baseball Lineage
Kieboom comes from a baseball family with deep international roots. His father was born in the Netherlands and played baseball on the Dutch junior national team and in the Honkbal Hoofdklasse, the top tier of Dutch professional baseball. That background helped shape Carter’s love for the game from an early age and gave the family a strong baseball identity in the Atlanta area.
Personal Life
Kieboom’s older brother, Spencer Kieboom, played catcher in the Washington Nationals organization and appeared in the major leagues with the club in 2018. The two brothers are among the more recent sibling tandems to have reached the major leagues, and Carter has frequently spoken about Spencer’s influence on his development as a player.
2025 Season Performance
Carter Kieboom’s 2025 season was split between Triple-A Salt Lake and a brief major league stint with the Los Angeles Angels. With the Bees, he put together one of the most consistent seasons of his career, batting .319 with nine home runs, 57 runs batted in, and 11 stolen bases across 93 appearances. His on-base skills and gap power were on full display, and he served as a steady veteran presence in the Salt Lake lineup.
On September 16, 2025, the Angels added Kieboom to their active roster, giving him a final opportunity to show what he could do in the major leagues. He appeared in three games for Los Angeles, going 2-for-8 with one run batted in. Although his big league opportunity was short, the strong Triple-A performance kept him firmly on the organization’s radar.
On October 22, the Angels removed Kieboom from the 40-man roster and sent him outright to Salt Lake, after which he rejected the assignment and elected free agency. Following the season, he signed a minor league deal with Cleveland in January 2026 and was later traded to the Philadelphia Phillies in March, setting the stage for his next chapter in the Phillies system.
