The surname Bizzarro and its variants have a clearly nickname-based origin, linked to the character or behaviour of the ancestor. According to E. De Felice, it derives from the name Bizzarro, formed from a nickname that described a person by their way of being, taking as its base the adjective bizzarro. This type of surname was frequent in the Middle Ages, when individuals were identified by distinctive personality traits.

From the point of view of diffusion, E. De Felice notes that the surname is present from the north to central Italy, and that the variant Bizzarro also appears in the Neapolitan area, which indicates a wide geographical expansion from a single origin.

For his part, F. De Laurentiis confirms this interpretation, explaining that the term bizzarro refers to someone "original, strange, out of the ordinary", that is, who does not follow the usual behaviours. Taken together, both interpretations agree in pointing to an origin based on a nickname that highlighted the personality of the individual, with a later evolution as a hereditary surname in different regions of Italy.