Bonucci punched a man who threatened him with a gun and demanded his watch, prompting the would-be thief to flee.
Italian media say the incident occurred earlier this week as Bonucci was leaving a Ferrari dealer with his wife and newborn son.
After Bonucci's punch, the would-be thief fled on a motorcycle with a waiting accomplice. Bonucci then reported the incident to police.
The 25-year-old Bonucci played a key role in helping Juventus win Serie A last season with an undefeated record. He also played in each match of Italy's run to the European Championship final earlier this year.
In August, Bonucci was cleared of match-fixing accusations.