Koutetsu no Hanappashira

Omaezaki Sanemichi was born into a near-perfect existence. His family is wealthy and powerful, and he's good-natured, smart, and athletic as well! All the girls at his high school dream of having a Cinderella-style romance with him, and, though they are desperately jealous of him, none of the boys can come up with a legitimate reason to publicly hate him.

But one day the unthinkable happens: Sanemichi's family's flagship company collapses, and his father flees. Sanemichi and his former servants, the teenage siblings Natsuno and Asasuzu and the absent-minded old man Furukawa, are left without a dime. Will Sanemichi be able to maintain his gentlemanly behavior despite the humiliation and many hardships that face him?

(Source: MangaHelpers)