William Muldoon (May 25, 1852 – June 3, 1933)[1] was an American Greco-Roman Wrestling champion, a physical culturist, and the first chairman of the New York State Athletic Commission.

Nicknamed "The Solid Man,"[2] Muldoon established himself as champion in Greco-Roman wrestling in the 1880s and over the years gained a remarkable measure of public influence that would continue through his days as a health farm proprietor in Westchester County and his service on NYSAC.

Showing a knack for strength athletics at a young age, Muldoon gained a local reputation as a standout in caber-tossing, weightlifting, sprinting and amateur wrestling.

In 1880, Muldoon gained recognition when he won the World Greco-Roman Heavyweight Championship with a win over title claimant Thiebaud Bauer.

His rise to prominence brought challengers from across the globe, including Edwin Bibby and Tom Cannon of England, Donald Dinnie of Scotland, "Mat" Sorakichi of Japan, Carl Abs of Germany, William Miller of Australia, and John McMahon and Clarence Whistler, the latter being Muldoon's opponent in a titanic seven-hour match in 1881, where neither could gain a single fall.

[6][7] In 1889 Muldoon trained John L. Sullivan for his famous 75-round fight against Jake Kilrain for the world heavyweight bare-knuckle boxing championship.

On May 28, Muldoon and Sullivan would have an exhibition wrestling bout contested under London Prize Ring Rules that ended on a 5–5 draw.

Muldoon would make his final public appearance as a wrestler in a charity exhibition match against Roeber at Madison Square Garden in 1894.

Ambassador to Great Britain Joseph Hodges Choate, publisher Ralph Pulitzer, Senator Chauncey Depew, Major General J. Franklin Bell, essayist Elbert Hubbard, novelist Theodore Dreiser and Secretary of State Elihu Root, who was sent to Muldoon by President Roosevelt.

Muldoon dedicated a Civil War monument to the town of Belfast, New York, listing the names of local veterans in 1915, including that of his older brother John.

It has just been discovered (through DNA) that William and Leonie had a child that was placed with the Sisters of Charity of New York and eventually placed on an Orphan Train ending up in Indiana.

Muldoon was a strong advocate of compulsory military service, equestrianism, physical culture and the Boy Scouts of America, citing the latter as the only organization left devoted to leadership-building for young men.