Picero is a rare surname in Italy, not documented in the classic onomastic repertoires. The most reasonable hypothesis links it to the surname Picerno, which is indeed documented, proper to the province of Potenza (Basilicata) and neighbouring areas of the Bari and Salerno zones, derived from the place name Picerno (Lucania), a medieval locality that gave rise to the demonym: Picero could be a reduced variant or an alteration of Picerno.

Another possible branch connects it with the family of Picaro, Picari, Picarelli and Picariello, present in Lazio, Campania, Apulia and Basilicata, derived from the Spanish term pícaro ('rogue, scoundrel'), a nickname established in southern Italy during the Spanish domination. A third hypothesis relates it to the surnames Pichi, Pico and Picone, derived from the medieval Latin name Picus ('woodpecker' in Italian, also the name of an ancient Roman divinity of agriculture).