Raffaele Forgione had hidden inside the box in a failed attempt to escape detection by police after they broke into the property.
Forgione, 37, was transferred to Poggioreale jail in Naples. A member of the Naples mafia or Camorra, he has already been sentenced to four years and 10 months in prison for extortion.
He is a member of the Camorra's La Montagna clan which operates in the northern area of the province of Naples.
Police said they believe Forgione had probably been hiding at the apartment in Caivano, on the outskirts of northern Naples "for some time".
The Camorra is fragmented into a series of crime families which have their strongholds in particular areas of Naples and the surrounding Campania region.