Francesco Palmeri was extradited to Italy following his arrest last December in New York, police said in a statement.
He stands accused of travelling to southern Italy and threatening a businessman in Matera, demanding repayment of a €1 million loan owed to New York’s Gambino mafia clan.
In order to intimidate the businessman, police said Palmeri was backed up by a few people linked to the criminal underworld.
The alleged mobster is said to be the number three of the Gambino clan, described by police as the “underboss” of the mafia family.
He was arrested alongside seven other people accused of being tied to the New York crime syndicate.