The IBO belt is not generally considered when deciding the status of an undisputed champion, due to the computerised system that the body uses for its rankings. The Ring championship title is also not factored into the undisputed champion status.

A unified champion is a fighter who holds belts from two or more bodies, but not necessarily all four major titles for the division.

Read next | Undisputed champion vs. unified champion

Oleksandr Usyk became the first undisputed world heavyweight champion in the four belt era when he defeated Tyson Fury on points in May 2024. That also made the Ukrainian the first undisputed heavyweight king since British fighter Lennox Lewis in 1999.

However, that only lasted five weeks despite Usyk never losing a fight. The IBF ordered him to vacate his belt to Daniel Dubois, because he did not fight their mandatory challenger next.

Here is the rundown of every undisputed champion in heavyweight history (the recognised sanctioning bodies have changed over the years).

List of every undisputed heavyweight champion

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