Yokohama DeNA BayStars The
Yokohama DeNA BayStars selected Imanaga in the first round of the
2015 NPB draft out of
Komazawa University. Imanaga signed with the
Canberra Cavalry of the
Australian Baseball League to play weeks 2–7 of the
2018–19 Australian Baseball League season In his six starts for the Cavalry, he posted a 4–0
win–loss record with a league-best 0.51
earned run average (ERA) over 35
innings pitched with 57
strikeouts to one
walk. By meeting the statistical recognition minimum (0.8IP per team game), Imanaga broke the league records for
WHIP (0.429),
H/9 (3.6),
BB/9 (0.3) and second-best ERA behind
Ryan Searle. Following his ABL stint, Imanaga posted a 13–7 2.91 ERA,
2019 Nippon Professional Baseball season, finishing second in wins and strikeouts only behind
Shun Yamaguchi in the Central League. On June 7, 2022, Imanaga pitched a
no-hitter against the
Hokkaido Nippon-Ham Fighters. He struck out nine and allowed one walk over 117 pitches. On September 6, 2023, Yokohama announced that they would
post Imanaga to
Major League Baseball (MLB) following the 2023 season.
Chicago Cubs 2024 On January 11, 2024, Imanaga signed a four-year, $53 million contract with the
Chicago Cubs that also contained a fifth-year option. The Cubs also had to pay $9.825 million to the Bay Stars in the form of a release fee. Imanaga pitched six shutout innings allowing just two hits with nine strikeouts in his first start for the Cubs on April 1, 2024. Through his first nine MLB starts, Imanaga compiled a 5-0 record with a then-league-leading 0.84 ERA. On September 4, Imanaga delivered the first seven innings of a combined no-hitter and 12–0 win over the
Pittsburgh Pirates.
Nate Pearson and
Porter Hodge both followed with one inning each. It was the
18th no-hitter and the second combined no-hitter in Cubs franchise history. Additionally, it was the first no-hitter at
Wrigley Field since 1972 when
Milt Pappas last threw a no-hitter there.
2025 Imanaga started for the Cubs on
opening day in 2025 against the
Los Angeles Dodgers in the
MLB Tokyo Series. In the game, Imanaga pitched four scoreless innings, allowing zero hits, and striking out two batters but got a no decision as the Cubs lost to the Dodgers in the game. He made 25 starts for Chicago, posting a 9-8 record and 3.73 ERA with 117 strikeouts across innings pitched. While the majority of Imanaga's following originates from
Japan, many fans across the
United States (particularly
Chicago Cubs supporters) have embraced his precise pitching style. Both at
Wrigley Field and via social media, Imanaga has cultivated a passionate international fan base. One particularly viral phenomenon among Chicago fans was the “
Shota Boys,” which originated during his first games with the Cubs early in the season. On November 4, 2025, the Cubs declined his three-year club option and Imanaga became a free agent. However, on November 18, he accepted the $22 million qualifying offer to remain with the Cubs for another season. ==International career==