In S07E08 of Smallville Savage appears under the guise or Curtis Knox, an alias he also uses in Legends of Tomorrow, when Chloe refers to him as a Jack the Ripper wannabe, he smiles and says "I was Jack the Ripper." He makes mention to being other historical figures as well, one of them being Napoleon Bonaparte. However, in Legends of Tomorrow he explains how he learned about the curative powers of blood from Jack the Ripper. Does that mean that he learned about it while he was Jack the Ripper or that Jack the Ripper told him? I thought perhaps it would have been changed in Legends of Tomorrow because the whole idea is that he stayed quite throughout history. Are there other references to him being/knowing historical figures elsewhere?
Yes, Savage has claimed to be other historical figures in other continuities.
Over the centuries, Savage's name appeared over and over again in Western history, as advisor to kings and pharaohs in Sumer, Egypt, and Europe. He claimed to have ruled hundreds of civilizations under hundreds of names: Khafre, Alexander the Great, Julius Caesar, Genghis Khan, and Vlad the Impaler, to name a few. He had also worked as close friends and advisers to the likes of Erik the Red, Napoleon Bonaparte, Ra's al Ghul, Otto von Bismarck and Adolf Hitler. He was the court physician in France, and even used the royal family for syphilis experiments.
Source. (Emphasis mine)
The paragraph has a footnote referencing Flash Vol 2 #14. In Final Crisis, he was also revealed to be Cain (the biblical figure).
As for him being Jack the Ripper vs learning from him, Smallville and Legends of Tomorrow are different stories, not set in the same universe. So in Smallville, he was Jack the Ripper, and in LoT, he only learned from him.