Eisenhower and Grant, as far as I know, never held a political office before POTUS.
Beat me to it, I was going to mention General Eisenhower never having been in elective office before becoming president.
However, when it comes to leadership and management experience, that is something to consider. Eisenhower had key experiences in that area, as he planned and executed the Normandy invasion, among other accomplishments as Supreme Allied Commander in Europe. Contrast with Obama never having had any executive experience of any kind in life before being elected president.