It seems to me that he would have cared about the country, since he was general during the Civil War.
And subsequently, I often hear that many administrations from the late 19th and early 20th centuries were corrupt, is there truth to this, and in what ways and why?
It's a relatively agreed-upon point, as far as Smith's or McFeely's biographies of Grant are concerned, that the qualities that made Grant a good general did not necessarily make him fit for the White House. Although there has been a largely negative attitude towards Grant's presidency due to tales of corruption and 8 of the 12 years of failed Reconstruction occurring under his watch, recent scholarship has suggested that Grant himself can really only be faulted simply as a less-than-able politician. While the finer points of politicking were handled by more able statesmen such as Hamilton Fish as Secretary of State, or George Boutwell as the Secretary of the Treasury, Grant himself tended to put a little too much unchecked trust in what sometimes turned out to be the wrong sort of people, who would abuse what was granted by the general-president. But although Grant's poor judgement in where he placed his trust can hardly be an indictable flaw, it was his reputation that was ultimately and perhaps permanently tarnished to a certain degree.