| No. | Won By | Won From | Location | Date |
|---|---|---|---|---|
| 1. | Gus Kallio | Charlie Fischer* | Chicago, IL | 8/7/28 |
| 2. | Hugh Nichols | Gus Kallio | ?? | 3/8/29 |
| 3. | Gus Kallio | Ralph Parquat and Ray Carpenter** | Columbus, OH | 1930 |
| 4. | George Sauer | Gus Kallio | ?? | 1932 |
| 5. | Gus Kallio | George Sauer | ?? | 7/32 |
| 6. | Gus Kallio | ??*** | ?? | 3/35 |
| 7. | Joe Gunther | Gus Kallio | Nashville, TN | 4/16/35 |
| 8. | Gus Kallio | Joe Gunther | ?? | 7/35 |
| 9. | Octavio Gaona | Gus Kallio | Mexico City, Mexico | 3/29/39 |
| 10. | Tarzan Lopez | Octavio Gaona | Mexico City, Mexico | 2/4/40 |
*This was the finals of a tournament to crown the first champion.
**The title was vacated when Nichols moved up to the light heavyweight division. Kallio was recognized as champion after two separate victories in Ohio.
***The circumstances of this title change are unknown.