Jackson Kowar Bio
Jackson Alexander Kowar (born October 4, 1996) is an American professional baseball pitcher for the Seattle Mariners of Major League Baseball (MLB). He previously played in MLB for the Kansas City Royals, the organization that drafted him in 2018. A right-handed pitcher, Kowar rose to national attention while starring at the University of Florida, where he helped the Gators win the 2017 College World Series. He made his major league debut in 2021 and has built a career shaped by perseverance through early struggles and significant injury setbacks.
Early Life and Background
Jackson Alexander Kowar was born on October 4, 1996, in Weddington, North Carolina, a small community outside Charlotte. He grew up in a family with baseball ties, as his father, Frank Kowar, had been a minor league pitcher in the Toronto Blue Jays organization in 1990. That family connection helped shape Kowar’s interest in pitching from a young age.
Kowar attended Charlotte Christian School in Charlotte, North Carolina, where he starred on the high school baseball team. He became a full-time pitcher in his sophomore year, working as the team’s closer. As a senior, he produced one of the strongest seasons in the state, going 10–1 with a 0.20 earned run average (ERA) and 118 strikeouts in 71 innings. His performance attracted national scouting attention, and he was selected by the Detroit Tigers in the 40th round of the 2015 MLB Draft, though he chose not to sign.
Path to Professional Baseball
After initially committing to play college baseball at Clemson University, Kowar was granted his release following a coaching change and instead chose to attend the University of Florida. At Florida, he quickly established himself as one of the top college pitchers in the country, rooming with future Royals teammate Brady Singer.
As a freshman in 2016, Kowar appeared in 12 games for the Gators, posting a 3–0 record, a 3.37 ERA, and 44 strikeouts in 34 and two-thirds innings before a collapsed lung ended his season in May. He returned stronger in 2017, going 12–1 to tie Florida’s best single-season record, while adding an 4.08 ERA and 84 strikeouts in 19 games. That summer, Kowar earned the save in the College World Series championship game, pitching one and two-thirds scoreless innings to clinch Florida’s 2017 national title. As a junior in 2018, he was named to the All-SEC second team, finishing 10–5 with a 3.04 ERA in 18 starts.
Jackson Kowar Career
Early Career (2018–2020)
The Kansas City Royals selected Kowar with the 33rd overall pick in the 2018 MLB Draft, and he signed for $2.1 million. He made his professional debut that July with the Lexington Legends of the Single-A South Atlantic League, going 0–1 with a 3.42 ERA in nine starts. He began 2019 with the Wilmington Blue Rocks of the High-A Carolina League, where he was named an All-Star, before being promoted to the Northwest Arkansas Naturals of the Double-A Texas League in June.
Across 2019, Kowar combined for a 7–10 record between High-A and Double-A while striking out 78 batters in 74 and one-third innings at the Double-A level alone. The 2020 minor league season was canceled due to the COVID-19 pandemic, and Kowar trained at the Royals’ alternate site during the abbreviated MLB year, staying ready for a future opportunity.
Kansas City Royals Breakthrough (2021–2023)
Kowar began the 2021 season with the Omaha Storm Chasers of the Triple-A East League, where he dominated with a 5–0 record, a 0.85 ERA, and 41 strikeouts in 31 and one-third innings. On June 6, 2021, the Royals announced he would be promoted to the major leagues to start against the Los Angeles Angels the following day. He was officially added to the active roster on June 7, 2021.
His MLB debut proved difficult, as Kowar allowed four earned runs, three hits, two walks, and three wild pitches before being removed in the first inning with only two outs. Across nine appearances and eight starts in his rookie year, he went 0–6 with an 11.27 ERA and 29 strikeouts in 30 and one-third innings. Despite those numbers, he was honored with the Royals’ Paul Splittorff Pitcher of the Year award as the franchise’s top minor league pitcher.
Kowar’s struggles continued in 2022 across both Omaha and Kansas City, where he combined for a 4–10 record, a 6.16 ERA at Triple-A, and a 9.77 ERA in 15 and two-thirds innings of relief work in the majors. In 2023, he bounced between Omaha and Kansas City, sticking with the Royals after a recall on August 17 and finishing the year with a 6.43 ERA in 23 relief appearances for the big league club.
Seattle Mariners Era (2023–Present)
On November 17, 2023, the Royals traded Kowar to the Atlanta Braves in exchange for pitcher Kyle Wright. He did not stay in Atlanta long, as on December 3, 2023, he was dealt along with Cole Phillips to the Seattle Mariners in a package that brought Jarred Kelenic, Marco Gonzales, and Evan White to the Braves. The trade gave Kowar a fresh start on the West Coast.
On March 10, 2024, the Mariners announced that Kowar had suffered a tear in his right ulnar collateral ligament, requiring Tommy John surgery and ending his 2024 season. It marked the first time in his career that he had been placed on the injured list. He was transferred to the 60-day injured list ahead of the 2025 season and made rehabilitation appearances with the Triple-A Tacoma Rainiers and the Arizona Complex League Mariners before being activated on May 28, 2025.
Driving Style and Strengths
Across both starting and relief roles, Kowar has leaned on a balanced mix of stuff and competitiveness. His college and minor league track record shows the ability to miss bats at a high rate when he is locating his pitches, with seasons of 78 strikeouts in 74 and one-third innings at Double-A and 41 strikeouts in 31 and one-third innings at Triple-A underscoring his swing-and-miss profile. He has shown the versatility to handle both starting and bullpen duties, an asset that has helped him stay on major league rosters.
Notable Events and Milestones
Kowar’s biggest amateur moment came in 2017, when he earned the save in the College World Series championship game to deliver Florida’s national title. His major league debut on June 7, 2021, and the Paul Splittorff Pitcher of the Year award the same season stand as his first significant professional milestones, while his return from Tommy John surgery in 2025 marks the latest chapter in his career.
Jackson Kowar Career Wins
Jackson Kowar has built his professional resume primarily on development statistics and team accomplishments rather than headline major league wins. His most celebrated victories came at the amateur level, including the 2017 College World Series title with Florida, followed by strong minor league seasons at Wilmington, Northwest Arkansas, and Omaha. His major league opportunities to this point have been limited, and he has not yet recorded a verified major league win.
Minor League Highlights
Kowar was named a Carolina League All-Star with the Wilmington Blue Rocks in 2019, and he turned in one of the top starts to any minor league season in 2021 with Omaha, going 5–0 with a 0.85 ERA and 41 strikeouts in 31 and one-third innings before his promotion. His role in the Royals’ Paul Splittorff Pitcher of the Year honor recognized that body of work.
Other Wins & Performances
Beyond his college and minor league success, Kowar helped the Gators win the 2017 College World Series, recording a save in the championship game. He has also progressed steadily through the Royals and Mariners organizations, earning opportunities at every level of professional baseball.
Jackson Kowar Family
Family Background and Racing Lineage
Jackson Kowar’s connection to professional baseball runs through his father, Frank Kowar, who was a minor league pitcher in the Toronto Blue Jays organization in 1990. That family background helped foster Jackson’s early love of the game and influenced his path to becoming a pitcher.
Personal Life
Jackson Alexander Kowar married Caroline Kowar, née Kerns, in 2024. The couple’s marriage was a notable off-field event during a year in which Kowar was recovering from Tommy John surgery.
2025 Season Performance
Jackson Kowar entered 2025 still recovering from the Tommy John surgery he underwent in March 2024. He was placed on the 60-day injured list before the season began and spent the early months working his way back through rehabilitation appearances with the Triple-A Tacoma Rainiers and the Arizona Complex League Mariners, building up his arm strength and refining his pitch mix.
On May 28, 2025, the Mariners activated Kowar from the injured list, giving him his first major league opportunity since the 2023 season. His return added depth to a Seattle pitching staff that has emphasized long-term development and versatility out of the bullpen and rotation.
Looking ahead, Kowar’s 2025 outlook centers on staying healthy, reestablishing his command, and carving out a consistent role with the Mariners. After years of adversity at the major league level and a significant injury, his activation marked an important step toward showing the form that once made him a first-round pick and a College World Series champion.