He made his NPB debut on March 27, 2021, pitching a scoreless inning with 2 strikeouts against the Chunichi Dragons.

After recording a stellar 0.55 ERA in 33 appearances to begin the year, Kuribayashi was named an NPB All-Star for the first time in his career.

[3] In 2021, Kuribayashi recorded 37 saves with a 0.86 ERA in 53 games and claimed the Central League's Rookie of the Year Award.

On June 6, 2023, Kuribayashi pitched a scoreless seventh inning against the Hokkaido Nippon-Ham Fighters, earning his first win in NPB.

He pitched in five games and recorded 2 wins and 3 saves, contributing to Japan's gold medal in the Olympics.