After being a mainstay for the Pro Wrestling NOAH promotion where he seized GHC Junior Heavyweight and Heavyweight gold, KENTA sought to test himself in America for five years. On his return to Japan in 2019, his long time friend Katsuyori Shibata pushed for KENTA to join NJPW, and at Dominion on June 9, he made his first appearance, vowing to be part of the G1 Climax. 

KENTA started strongly in the G1, but he was met with boos from a crowd who didn’t see KENTA as one of their own. On the last night of the G1, he was to tag with Tomohiro Ishii and YOSHI-HASHI against a BULLET CLUB trio of Bad Luck Fale, Tama Tonga and Tanga Loa. Midway through the match however, he refused to tag Ishii and dropped off the apron. A Go2Sleep to Ishii later, and KENTA had joined BULLET CLUB. As BULLET CLUB instilled a ‘win at all costs’ mentality in KENTA, he took the approach to victory, winning the NEVER Openweight Championship, and, after nearly two years of chasing, the IWGP United States heavyweight Championship.

KENTA’s reign with the US gold would end in a violent war with Hiroshi Tanahashi that put him on the injured list. When healed, he started 2023 gunning for the Ace once again, while also challenging Fred Rosser for the STRONG Openweight Championship at Battle in the Valley.