F. Miranda explains that Bertolini belongs to an extensive family of surnames that have as their base the hypocoristic of the medieval name Berto, obtained by aphaeresis —that is, by the dropping of the initial syllables— from names of Germanic origin ending in -berto, such as Alberto, Adalberto, Lamberto, Roberto or Umberto. It can also be understood as a direct continuation of Germanic names already autonomous since the 7th century, attested in Italy in the Latinised forms Bertus or Berto, of probable Gothic and later Lombard and Frankish tradition, derived from the Germanic adjective berhta, "splendid, illustrious, famous".

F. De Laurentiis links it more directly with Bèrti, a form that represents one of the intermediate derivatives of that same base name.

Miranda notes that Bertolini is a typically Piedmontese surname, with presence also in Sicily —in areas such as Palermo, Trapani, Agrigento, Catania, Ragusa, Messina and Enna— and in other regions such as Lombardy, Liguria, Lazio and Campania.