Jack O'Brien (South Side) boxer
- bouts
- 29
- won
- 17
- lost
- 11
- draw
- 1
- Status
- inactive
- Division
- featherweight
- Debut
- 1900-02-10
- Height
- -
- Reach
- -
- Age
- -
- Born
- -
- Death
- -
- Nationality
- USA
| Date | Opponent | Last Opponents' Results | Place | Result |
|---|---|---|---|---|
| 1910-08-12 | Red Cornett | WL | Dreamland Rink, San Francisco | WIN Points |
| 1907-07-12 | Joe Riley | L | Dreamland Pavilion, San Francisco | LOST Points |
| 1907-04-19 | Jim Ford | WWWWDW | Dreamland Pavilion, San Francisco | WIN Points |
| 1906-12-07 | Jack O'Brien | WLWLWL | Dreamland Pavilion, San Francisco | LOST Points |
| 1905-03-03 | Young Dempsey | WWWWWW | Woodward's Pavilion, San Francisco | LOST Points |
| 1905-02-10 | Johnny Crowe | WWWWDD | Woodward's Pavilion, San Francisco | LOST Points |
| 1905-01-18 | Nig Normart | WLW | Madera | LOST Technical knockout |
| 1905-01-13 | Abe Label | LLWWWL | Woodward's Pavilion, San Francisco | WIN KO |
| 1904-12-30 | Bob Ritchie | debut | Mechanic's Pavilion, San Francisco | WIN Points |
| 1904-12-13 | Joe Carroll | WWWWW | Woodward's Pavilion, San Francisco | WIN Points |
| 1904-10-14 | Jack O'Brien | WWLWLW | Woodward's Pavilion, San Francisco | WIN Points |
| 1904-08-25 | Jack O'Brien | WWLWL | Woodward's Pavilion, San Francisco | LOST KO |
| 1904-06-16 | Abe Label | LWWWWL | Woodward's Pavilion, San Francisco | WIN Points |
| 1904-05-31 | Abe Label | LLWWWW | Mechanics' Pavilion Annex, San Francisco | WIN Points |
| 1904-03-18 | Joe Leahy | WLWWWL | Woodward's Pavilion, San Francisco | WIN Points |
| 1904-03-04 | Jack O'Brien | WW | Mechanics' Pavilion Annex, San Francisco | WIN Points |
| 1904-02-12 | Al Elkins | WWWWW | Mechanic's Pavilion, San Francisco | WIN Points |
| 1904-02-05 | Charles Yeager | debut | Mechanic's Pavilion, San Francisco | WIN KO |
| 1903-09-18 | Abe Label | WLL | Mechanic's Pavilion, San Francisco | WIN Points |
| 1903-07-02 | Dick Cullen | WWLWWW | Mechanics' Pavilion Annex, San Francisco | LOST Points |
| 1903-03-06 | Abe Label | W | Mechanic's Pavilion, San Francisco | WIN Points |
| 1902-10-17 | Charlie Webber | L | San Francisco A.C., San Francisco | WIN KO |
| 1902-09-19 | Dick Cullen | LLLLWL | San Francisco A.C., San Francisco | LOST Points |
| 1902-05-09 | Rufe Turner | WDLWWW | Sacramento | LOST Technical knockout |
| 1900-11-22 | George Curran | W | Stockton Athletic Club, Stockton | LOST KO |
| 1900-02-10 | Joe (Spider) Welsh | LWWWL | San Francisco | LOST KO |