E. De Felice notes that this surname derives from a nickname formed, with various motivations, from the term imperatore ("emperor"; feminine: imperatrice), with a characteristic presence in southern Italy, especially in Campania.

E. Rossoni specifies that Imperatore, together with its variants, derives from the medieval name Imperatore, which arose as a mark of honour and prestige from the political office of the same name —as with medieval names such as Principe, Marchese or Senatore. He considers a direct derivation from the imperial title less likely. The form Imperatore has its main epicentre in the Naples area, with an independent core in San Mauro Forte, in the Matera area.

Rossoni adds that the variant Imperatori is predominant in Lazio and the Marche, with the greatest concentration in the Rieti, Rome, Pesaro and Ascoli Piceno areas, as well as isolated pockets in northern Italy. The variant Imperatrice is more typically southern, with a main core in the Naples area and secondary cores in the Taranto and Foggia areas.