Carter Alswinn Kieboom Bio
Carter Alswinn Kieboom, born on September 3, 1997, in Marietta, Georgia, 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 the Los Angeles Angels, and he made his major league debut in 2019. The son of a Dutch-born baseball player, Kieboom was a first-round selection in the 2016 MLB Draft and worked his way through the Washington minor league system before reaching the big leagues.
Early Life and Background
Carter Alswinn Kieboom was born on September 3, 1997, in Marietta, Georgia, and grew up in a household with deep baseball roots. His father was born in the Netherlands, played for the Dutch junior national team, and competed in the Honkbal Hoofdklasse, the top professional baseball league in the Netherlands. That family background gave Carter Alswinn Kieboom early exposure to the game and a clear understanding of what it took to pursue baseball at a high level.
Kieboom attended George Walton Comprehensive High School in Marietta, Georgia, where he developed into a top prospect. He committed to play college baseball for the Clemson Tigers at Clemson University, but his path turned professional before he ever suited up for the Tigers. He grew up alongside his brother, Spencer Kieboom, who also reached the majors, playing briefly for the Nationals in 2018. Together, the brothers gave the family two sons who earned time on a big league roster.
Path to Baseball
Coming out of George Walton Comprehensive High School, Carter Alswinn Kieboom emerged as one of the most promising high school position players in his draft class. His commitment to Clemson University kept his college option open, but his performance on the showcase circuit convinced the Washington Nationals to make him a first-round pick in the 2016 Major League Baseball draft.
Kieboom announced that he would sign with the Nationals on June 11, 2016, choosing professional baseball over college. He spent that summer with the rookie-level Gulf Coast League Nationals, where he batted .244 with four home runs and 25 runs batted in. The early pro assignment let him adjust to the daily routine of the minor leagues while the organization mapped out his long-term development plan.
Carter Alswinn Kieboom Career
Early Career (2016–2018)
Kieboom opened his professional career in the rookie-level Gulf Coast League in 2016, then moved to the Single-A Hagerstown Suns in 2017, where he was hitting .333 with six home runs and 20 runs batted in before a hamstring injury on May 12 sent him to the disabled list. After his return, he was named to the Northern Division All-Star team in the South Atlantic League, and both Baseball America and MLB Pipeline ranked him as the Nationals’ fourth-best prospect that year.
In 2018, Kieboom played for the High-A Potomac Nationals and was named a Carolina League All-Star, going 3-for-5 with a home run in the All-Star Game. Following the Midsummer Classic, he was promoted to the Double-A Harrisburg Senators and homered in his first game at the higher level. He also represented Team USA in the All-Star Futures Game at Nationals Park, marking him as one of the top young players in the organization.
Washington Nationals Breakthrough (2019–2021)
Kieboom began the 2019 season with the Fresno Grizzlies of the Triple-A Pacific Coast League before the Nationals purchased his contract on April 26 and added him to the major league roster. He made his MLB debut that night against the San Diego Padres and hit a home run for his first major league hit, an immediate statement from one of the team’s top prospects. He played 11 games for Washington that year, and although he finished with a .128 average and two home runs, he was part of a clubhouse that won the World Series over the Houston Astros.
After veteran third baseman Anthony Rendon departed in free agency, manager Dave Martinez told reporters in January 2020 that Kieboom would move to third base full time and serve as Rendon’s replacement. The shortened 2020 campaign was a difficult adjustment, as he played 33 games and hit .202/.344/.212 with no home runs and 9 runs batted in before a left wrist contusion ended his season early. In 2021, he played 62 games, his most during his time in Washington, and hit .207 with six home runs as he continued to search for consistency at the plate.
Injury Period and Return (2022–2023)
On March 20, 2022, it was announced that Carter Alswinn Kieboom would miss four to six weeks while recovering from a flexor mass strain near his right elbow, and he was placed on the 60-day injured list the following day. On May 20, the Nationals announced that he would require Tommy John surgery, which ruled him out for the entire 2022 season. The procedure and long recovery marked a significant setback in his development as the franchise’s planned everyday third baseman.
Kieboom began the 2023 season in extended spring training before being activated by the Rochester Red Wings of the Triple-A International League in May. A June oblique muscle injury sent him back to the injured list, but upon his return to the majors, he hit a home run in his first at-bat. In 26 games for Washington, he batted .207/.266/.368 with 4 home runs and 11 runs batted in, offering a small reminder of the offensive potential that had made him a first-round pick.
Los Angeles Angels Era (2024–2025)
On March 13, 2024, the Washington Nationals removed Carter Alswinn Kieboom from the 40-man roster and sent him outright to Triple-A Rochester. He played 91 games for the Red Wings that year, slashing .265/.365/.386 with seven home runs and 42 runs batted in, and he elected free agency on November 4. Looking for a fresh start, he signed a minor league contract with the Los Angeles Angels on December 6, 2024.
In 2025, Kieboom played 93 games for the Triple-A Salt Lake Bees, batting .319/.368/.449 with nine home runs, 57 runs batted in, and 11 stolen bases. On September 16, the Angels added him to their active roster, and he went 2-for-8 with one run batted in over three big league appearances. On October 22, Los Angeles removed him from the 40-man roster and sent him outright to Salt Lake, after which he rejected the assignment and elected free agency.
Carter Alswinn Kieboom Career Wins
Although individual pitching or batting titles are limited, Carter Alswinn Kieboom has built a resume of personal achievements, league honors, and postseason experience. He was a South Atlantic League Northern Division All-Star in 2017, a Carolina League All-Star in 2018, and an All-Star Futures Game participant in both 2018 and 2019. He is also a member of the 2019 Washington Nationals, who won the World Series, although he did not appear in any postseason action that fall.
Carter Alswinn Kieboom Family
Family Background and Baseball Lineage
Carter Alswinn Kieboom’s connection to baseball runs through his father, who was born in the Netherlands, represented the Dutch junior national team, and played in the Honkbal Hoofdklasse. That international background gave Carter a unique perspective on the game from a young age. His brother, Spencer Kieboom, was also a professional catcher who played for the Washington Nationals in 2018, making the Kieboom family one of the few brother combinations to appear in a major league box score for the same organization.
2025 Season Performance
Carter Alswinn Kieboom’s 2025 campaign began in the Angels’ minor league system as he worked his way back into big league form. At Triple-A Salt Lake, he was one of the Bees’ most productive hitters, posting a .319/.368/.449 line with nine home runs, 57 runs batted in, and 11 stolen bases across 93 games. His strong on-base skills and power output were the best numbers of his professional career, signaling a return to the offensive form the Nationals once hoped he would deliver at the major league level.
On September 16, the Los Angeles Angels selected his contract and added him to the active roster, giving him a brief late-season look in the majors. He appeared in three games and went 2-for-8 with one run batted in before the Angels made their offseason roster decisions. On October 22, Los Angeles removed him from the 40-man roster and sent him outright to Salt Lake, and Carter Alswinn Kieboom rejected the assignment and elected free agency, leaving his next stop in professional baseball open heading into the offseason.