The authors agree that this surname derives from the place name Caserta, a city of Campania. E. Rossoni and F. Miranda specify that the name comes from the Latin casae hirtae, where casae means "huts" or "cluster of dwellings" and hirtae alludes to the elevated position of the ancient settlement on steep terrain. G. P. Holmes gathers a variant of that etymology with the medieval Latin formula "bristly house" or "village located in an impenetrable site", which reflects the same topographic sense.

E. De Felice notes that the surname spread in a scattered way in southern Italy, with greater concentration in the Naples area. Rossoni places it in Campania, Puglia and Calabria. Miranda offers the most detailed distribution: besides Campania —with presence in the Naples, Caserta and Benevento areas— and Calabria, Puglia and Basilicata, he documents it also in Sicily, Lombardy, Piedmont, Lazio, Tuscany and Liguria. In Sicily it appears with particular frequency in the Catania area —in localities such as Maletto, Biancavilla, Belpasso and Adrano—, and also in the Palermo, Messina, Ragusa, Syracuse and Enna areas.