Defeated Kurt Angle on February 17, 2008 on the Circuit 2008 New Japan ISM tour to unify the NJPW and IGF versions of the IWGP Heavyweight Championship.
Vacated due to Lesnar being unable to defend the championship because of "problems with a working visa". Lesnar refuses to turn over the championship belt, and later is recognized by the Inoki Genome Federation as their first champion, using the same belt.
Defeated Yoshihiro Takayama to unify the IWGP Heavyweight Championship with the NWF Heavyweight Championship on January 4, 2004, at Wrestling World 2004.