King's Kung-Fu& Tai Chi

Philadelphia Jack O'Brien

American boxer (1878–1942)

Born
17 January 1878, Philadelphia
Died
12 November 1942
Citizenship
United States
Sport
boxing
Discipline
light heavyweight
Occupation
boxer
Height
179 cm (5 ft 10 in)
Recorded fight record
100 wins, 6 losses, 16 draws

Joseph Francis Hagan (better known as Philadelphia Jack O'Brien) (January 17, 1878 – November 12, 1942) was an American world light heavyweight boxing champion in 1905 when he defeated Bob Fitzsimmons for the universal world title. Rather than defending his title, O'Brien instead abandoned it in order to fight at heavyweight. Nat Fleischer, founder and editor of The Ring Magazine, ranked O'Brien as the No. 2 All-Time Light Heavyweight, and famed boxing promoter Charley Rose ranked him as the No. 3 All-Time Light Heavyweight.

O'Brien was inducted into the Ring Magazine hall of fame in 1968, the World Boxing Hall of Fame in 1987, and the International Boxing Hall of Fame in 1994.

Awards and honours

External links

Facts from Wikidata Q2779046 (CC0); quoted introduction from English Wikipedia (CC BY-SA 4.0). Data retrieved 2026-10-22.

Data: Wikidata (CC0 1.0); Wikipedia (English) (CC BY-SA 4.0). Retrieved 2026-10-22.