The authors agree that the surname derives from a compound of Germanic origin formed from alja and berhta. F. Miranda specifies that the original name was Alipertus, present in Italy from the 7th century, which evolved towards Alibertus and finally towards Alberto, meaning "very famous". V. Blunda, on the other hand, interprets alja as "other" or "different" —and not as "entirely" or "very"—, which leads to a different translation: "another bright one" or "second in fame". Blunda also notes that berhta is one of the most productive elements of Germanic anthroponymy, present in names such as Roberto, Alberto and Umberto.

Miranda places the main focus of diffusion of the surname in the Campania region, especially in the areas of Naples and Salerno, with the municipality of Siano as the historical centre of radiation for belonging to the old Lombard Duchy of Benevento. He also records presence in Piedmont —areas of Turin and Asti—, Lombardy —Milan area—, Lazio and Sicily, with clusters in the areas of Messina, Catania, Palermo, Trapani and in the Enna area. Blunda, for his part, stresses that the variants with vocalic prosthesis are testimony to the dialectal adaptation of the surname in southern Italy.

Miranda also documents the variant Aliberto, present mainly in Sicily —areas of Messina, Enna, Trapani, Palermo and Catania— and with secondary presence in Campania, Tuscany and Lombardy.