Jack O'Brien boxer
- bouts
- 4
- won
- 1
- lost
- 3
- draw
- 0
- Status
- inactive
- Division
- lightweight
- Debut
- 1922-01-21
- Height
- -
- Reach
- -
- Age
- -
- Born
- -
- Death
- -
- Nationality
- USA
| Date | Opponent | Last Opponents' Results | Place | Result |
|---|---|---|---|---|
| 1923-12-01 | Guy Chiaro | L | 9th Regiment Armory, Brooklyn | LOST KO |
| 1923-03-31 | Petey Hayes | WWDWWW | 9th Coast Defense Armory, New York | LOST KO |
| 1922-02-04 | Young Wallace | debut | 9th Regiment Armory, Brooklyn | LOST KO |
| 1922-01-21 | Joe Paul | LLWLLL | 9th Coast Defense Armory, New York | WIN KO |