Jack O'Brien (California) boxer
- bouts
- 2
- won
- 1
- lost
- 1
- draw
- 0
- Status
- inactive
- Division
- lightweight
- Debut
- 1892-03-18
- Height
- -
- Reach
- -
- Age
- -
- Born
- -
- Death
- -
- Nationality
- USA
| Date | Opponent | Last Opponents' Results | Place | Result |
|---|---|---|---|---|
| 1892-04-07 | Bobby Dobbs | WWWWWL | San Francisco | LOST KO |
| 1892-03-18 | Bobby Dobbs | WWWWWW | Pastime A.C., San Francisco | WIN KO |