4. AJ Styles
There is no denying that AJ Styles made a massive impact on NJPW when he became a member of the Bullet Club in 2014. From the minute that he made his presence known on April 6th at Invasion Attack, it was clear that he wanted to take the Heavyweight title off champion Kazuchika Okada. It was a belt that he won at Wrestling Dontaku. He became the sixth Gaijin to win the title and the first since Brock Lesnar in 2005. His second reign came then came again in a year later.
During his reigns, he defended the title both in Japan and America against the likes of Michael Elgin and Kota Ibushi. It was also the time where more international fans were drawn to the product. Many fans have credited Styles with helping to begin their journey into the world of New Japan but also Japanese wrestling in general.
In total, Styles had two successful title reigns spanning over 300 days. For many, it was his run in New Japan that helped to cement his status as one of the best wrestlers in the world.
3. Keiji Mutoh
With four Heavyweight title reigns lasting a combined 1,238 days between 1992 and 2009, it is impossible not to put Japanese legend Keiji Muto on this list. Whether as Muto or his alter ego The Great Muta, they are reigns that have cemented his legacy in New Japan as one of the original Three Musketeers.
His first reign in 1992 was as the Great Muta after defeating fellow legend Riki Choshu during the 1992 G1 Climax Special in Fukuoka. From there, it was a successful first reign lasting 400 days with five defences against the likes Scott Norton, Shinya Hashimoto, and Sting to name a few. Over the next decade and a half, Mutoh would go on to have three more reigns. Even at the age of 46, he had great matches between top stars like Hiroshi Tanahashi and Shinsuke Nakamura.
It was the high quality of matches Mutoh put on alongside his charisma and style within the ring that has made him such a legacy in NJPW.