Takagi made his Nippon Professional Baseball debut for the Yomiuri Giants on March 29, 2015. In his debut season, Takagi recorded a 9-10 record and 3.07 ERA in 27 games (26 of them starts). The following season, Takagi pitched in 25 games for Yomiuri, posting a 5-9 record and 4.31 ERA with 91 strikeouts in 117.0 innings of work. In 2017, Takagi made 16 appearances for the Giants, recording a 2.63 ERA with 15 strikeouts in 27.1 innings pitched.[1]
Saitama Seibu Lions
On December 17, 2017, Takagi was selected by the Saitama Seibu Lions as compensation for Ryoma Nogami's departure in free agency. In 2018, Takagi struggled to an 8.69 ERA with 10 strikeouts in 8 appearances for the club. In 2019, Takagi made 2 appearances for Seibu, but allowed 2 earned runs in 2.1 innings pitched. Takagi became a free agent following the season.
On January 10, 2020, Takagi signed with the Leones de Yucatán of the Mexican League.[2] Takagi did not play in a game in 2020 due to the cancellation of the Mexican League season because of the COVID-19 pandemic.[3] On February 23, 2021, Takagi was released by the Leones.[4]
Kanagawa Future Dreams
On March 12, 2021, Takagi signed with the Kanagawa Future Dreams of the Baseball Challenge League.[5] On October 4, 2021, Takagi left the team.
On July 14, 2022, Takagi was traded to the Bravos de León in exchange for IF Carlos Rivero.[9] He made two starts for León, struggling to an 0–2 record and 19.29 ERA with 2 strikeouts across 4+2⁄3 innings of work. Takagi was released by the Bravos on July 31.[10]
Kanagawa Future Dreams (second stint)
On January 4, 2023, Takagi returned to the Kanagawa Future Dreams of the Baseball Challenge League as a player and coach.[11]
He was named to the team's Opening Day roster in 2024.[12]