The undisputed champion in boxing is a fighter who holds all belts from the four major governing bodies: the WBC, WBA, WBO and IBF. 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.
MORE: Undisputed champion vs. unified champion
Anthony Joshua and Tyson Fury are set to fight twice in 2021, holding the IBF, IBO, WBA, WBO, WBC and Ring titles between them. Assuming Joshua does not lose to Kubrat Pulev and does not vacate his WBO belt before he fights Fury, the winner would become the undisputed heavyweight fighter of the world.
Here is the rundown of every undisputed champion in heavyweight history. The recognized sanctioning bodies have changed over the years, and there has not yet been a four-belt undisptued champ in the heavyweight division.
List of every undisputed heavyweight champion
| Reign started | Reign ended | Boxer | Belts |
| July 24, 1922 | Sept. 23, 1926 | Jack Dempsey | NYSAC, NBA |
| Sept. 23, 1926 | July 31, 1928 | Gene Tunney | NYSAC, NBA |
| June 12 1930 | Jan. 7, 1931 | Max Schmeling | NYSAC, NBA |
| June 21, 1932 | June 29, 1933 | Jack Sharkey | NYSAC, NBA |
| June 29, 1933 | June 14, 1934 | Primo Carnera | NYSAC, NBA |
| June 14, 1934 | June 13, 1935 | Max Baer | NYSAC, NBA |
| June 13, 1935 | June 22, 1937 | James J. Braddock | NYSAC, NBA |
| June 22, 1937 | March 1, 1949 | Joe Louis | NYSAC, NBA |
| Sept. 27, 1950 | July 18, 1951 | Ezzard Charles | NYSAC, NBA |
| July 18, 1951 | Sept. 23, 1952 | Jersey Joe Walcott | NYSAC, NBA |
| Sept. 23, 1952 | April 27, 1956 | Rocky Marciano | NYSAC, NBA |
| Nov. 30, 1956 | June 26, 1959 | Floyd Patterson | NYSAC, NBA |
| June 26, 1959 | June 20, 1960 | Ingemar Johansson | NYSAC, NBA |
| June 20, 1960 | Sept. 25, 1962 | Floyd Patterson | NYSAC, NBA |
| Sept. 25, 1962 | July 22, 1963 | Sonny Liston | NYSAC, WBA |
| July 22, 1963 | Feb. 25, 1964 | Sonny Liston | WBC, WBA |
| Feb. 25, 1964 | Sept. 19, 1964 | Muhammad Ali | WBC, WBA |
| Feb. 6, 1967 | April 28, 1967 | Muhammad Ali | WBC, WBA |
| Feb. 16, 1970 | Jan. 22, 1973 | Joe Frazier | WBC, WBA |
| Jan. 22, 1973 | Oct. 30, 1974 | George Foreman | WBC, WBA |
| Oct. 30, 1974 | Feb. 15, 1978 | Muhammad Ali | WBC, WBA |
| Feb. 15, 1978 | March 18, 1978 | Leon Spinks | WBC, WBA |
| Aug. 1, 1987 | Feb. 11, 1990 | Mike Tyson | WBC, WBA, IBF |
| Feb. 11, 1990 | Oct. 25, 1990 | James "Buster" Douglas | WBC, WBA, IBF |
| Oct. 25, 1990 | Nov. 13, 1992 | Evander Holyfield | WBC, WBA, IBF |
| Nov. 13, 1992 | Dec. 14, 1992 | Riddick Bowe | WBC, WBA, IBF |
| Nov. 13, 1999 | April 29, 2000 | Lennox Lewis | WBC, WBA, IBF |