Don Calogero is, in the words of Prince Fabrizio, the "new man" of Italy. He's a scheming capitalist who knows how to squeeze a situation for every penny it's worth. Because of this attitude, Don Calogero has become the richest man in his town, richer even than Fabrizio. As Fabrizio's friend Ciccio says,
"Don Calogero is very rich, and very influential too; that he's a miser (when his daughter was at school he and his wife used to eat a fried egg between them) but knows how to spend when he has to." (3.43)
On this level, it's possible to admire Calogero as an enterprising guy who has made his own fortune, unlike Fabrizio, who's been born into his.
On the other hand, Calogero is really rude and rough around the edges. He lacks a lot of the social niceties of people who've had money for many generations. As Ciccio adds, Calogero is:
"… a scourge of God, Excellency, a scourge of God. And we haven't seen the beginning of Don Calogero's career. In a few months he'll be Deputy in the Turin Parliament […] that's Don Calogero, Excellency: the new man: a pity he has to be like that, though." (3.43)
Don Calogero is destined to gain power in the new Italy, and people like Fabrizio are destined to become relics of a former time. When offered a position as a senator in the new Italian government, Fabrizio turns down the position and recommends Calogero for it, saying that he's the type of man whom the government will want heading forward. Fabrizio's time is done, and the age of Calogero is just beginning.