An early version of this championship was introduced in 1983 for the winner of the IWGP League 1983. Since then, the championship was defended annually against the winner of the IWGP League of the year. The current IWGP Heavyweight Championship arrived only on 1987, replacing the old version.
The current version is defended regularly and is the top championship of the NJPW.
Throughout the history of the championship, several wrestlers have been forced to relinquish the title due to an inability to participate in title defenses. When a wrestler has been injured or unable to compete for other reasons, tournaments have been held to determine the new champion.
In 2006, Brock Lesnar was stripped of the title for refusing to defend it, claiming he was owed money by NJPW. The company went on to crown a new champion, while Lesnar kept the physical belt. He signed with Antonio Inoki's Inoki Genome Federation (IGF) in 2007, and lost the championship to Kurt Angle on the promotion's inaugural event. Angle later lost the belt in a unification match to the NJPW-recognized champion Shinsuke Nakamura in 2008.
Overall, there have been 68 reigns shared among 29 wrestlers. Title changes happen at NJPW-promoted events. Big Van Vader, Salman Hashimikov, Scott Norton, Bob Sapp, Brock Lesnar, A.J. Styles, Kenny Omega and Jay White are the eight non-Japanese wrestlers to have held the title, with Hashimikov being the first and only Soviet-born champion, while Omega is the first Canadian champion. The inaugural champion was Inoki, who defeated Masa Saito on June 12, 1987, in a tournament final. Hiroshi Tanahashi holds the record for most reigns, with eight. At 720 days, Kazuchika Okada's fourth reign is the longest in the title's history. Okada has the most successful defences in that reign with 12 and with a combined four reigns, also holds the record for most days as champion at 1,516. Kensuke Sasaki's fourth reign holds the record for shortest reign at 16 days. Over his eight reigns, Tanahashi successfully defended the title 28 times, the most of any champion. With zero, Big Van Vader's first and third reigns, Salman Hashimikov's only reign, Riki Choshu's first reign, Tatsumi Fujinami's third and fifth reigns, Masahiro Chono's only reign, Genichiro Tenryu's only reign, Scott Norton's second reign, Hiroyoshi Tenzan's first and third reigns, Kensuke Sasaki's fourth reign, Kazuyuki Fujita's third reign, Manabu Nakanishi's only reign and Hiroshi Tanahashi's eighth reign are all tied for least successful defenses.
Jay White is the current champion in his first title reign. He defeated Hiroshi Tanahashi on February 11th, 2019, at NJPW's The New Beginning in Osaka event to win the title.