|Representing the United States|
|1904 St. Louis||Lightweight|
|1904 St. Louis||Welterweight|
He won two medals in Boxing at the 1904 Summer Olympics, one of only a four boxers to capture more than one medal in the same Olympics. George Finnegan, Charles Mayer, and Oliver Kirk, who also competed in St. Louis, were the others.
- "Harry Spanjer". Olympedia. Retrieved 3 February 2021.
- Evans, Hilary; Gjerde, Arild; Heijmans, Jeroen; Mallon, Bill; et al. "Harry Spanjer". Olympics at Sports-Reference.com. Sports Reference LLC. Archived from the original on 2020-04-17.