Have any other U.S. Presidents besides Trump run a business while in office? If so, who were they and why is this not commonly known?
Other presidents had the good sense to divest of their business interests upon election. They were mature enough to recognize the conflict of interest, plus division of their attention. They had the wisdom to recognize that decisions they made as chief executive of the nation could, directly or indirectly, affect their own business interests, so they detached themselves from the operation of those businesses.
Only Trump sought to profit through the office. Only Trump diverted clients to his businesses, rather than let them make their own choices in the matters.
Only Trump debased the office this way.