After weeks of New Japan Pro-Wrestling (NJPW) airing videos of a mystery man targeting IWGP United States Champion Juice Robinson, Jon Moxley was revealed as the culprit in May 2019, challenging Robinson for a title match at the final night of the Best of the Super Juniors 26 event on June 5.
At the event, he defeated Robinson in his NJPW in-ring debut to win the IWGP United States Championship. Following Moxley's original challenge, AEW CEO Tony Khan stated that Moxley will be able to take independent and international bookings during the summer before AEW's television deal starts in the fall.
However during an interview with Nikkan Sports, Good clarified that " there is no problem in fighting in New Japan while belonging to AEW. In the future, I can always show up in Japan and have matches." According to Fightful, Good's contract will last until Wrestle Kingdom 14 in January 2020.
At Dominion 6.9 in Osaka-jo Hall on June 9, Moxley defeated young lion Shota Umino, before declaring himself an entrant for the 2019 G1 Climax. In the aftermath of the match, he also publicly claimed his appreciation for Umino and stated that he was looking forward to partnering up with him; Umino subsequently became Moxley's manager and tag team partner.
At the G1 Climax, Moxley, competing in the B block, won his first five matches against Taichi, Jeff Cobb, Tomohiro Ishii, Shingo Takagi and Tetsuya Naito. During a long interview with NJPW’s official website, Moxley talked about Wrestle Kingdom: "100% I plan to be at the Tokyo Dome.
I don’t know who I’ll be facing, whether I’m still US Champion. But I’ve been in Wrestlemania, in the G1, and this is the next step. Anyone who’s anyone in Japan has competed in the Tokyo Dome, so I absolutely plan on being there”.