A 52-year-old Staten Island man lived large on the backs of old folks by running an old-fashioned con, according to the feds.

Joseph Mazella was arrested yesterday morning and charged with securities fraud, wire fraud and money laundering.

The feds say he ran a $12 million Ponzi scheme under the cover of a real-estate investment firm, the Great Atlantic Group.

The Navy vet allegedly posed as a white knight out to rescue people at risk of losing their homes.

Instead, the feds say, he tricked the mostly elderly investors into forking over money, then used it to pay off earlier investors, cover his mortgage and Porsche, and subsidize family expenses.