The Yona Schimmel Knish Bakery on Manhattan’s Lower East Side isn’t the likeliest spot for a sit-down with a onetime wise guy, but Louis Ferrante is hardly your typical ex-mobster.

An intense, brassy, fast-talking bantam weight, the 38-year-old Ferrante, who’s joined me to talk about his new memoir, “Unlocked: A Journey from Prison to Proust” (Harper, $25.95), can expound on just about any topic — penal reform, world history, literature, theology, you name it — and peppers his remarks with references to Churchill, Napoleon, and Disraeli. There’s a lot about him that’s unexpected. Consider this: Ferrante, a former Gambino family associate raised in a Catholic home, is now an Orthodox Jew.

A hardboiled tale of crime, punishment, and redemption, “Unlocked” charts Ferrante’s violent life pulling off heists for the Gambinos and his eventual downfall in 1994, when a mighty trifecta of the Secret Service, the FBI, and Nassau County put him behind bars. Ferrante took a plea and served nine years in several New York jails.

He doesn’t downplay the brutality of life inside — sexual abuse was rampant and Ferrante had to fend off would-be attackers — but doing time would change his life for the better. Prison became a kind of university and spiritual retreat: putting his mob days behind him, Ferrante turned to books, devouring Caesar’s “Gallic Wars” and “Anna Karenina”; started to write and embraced Judaism as he tried to atone for his past misdeeds.

It’s a pretty incredible story, but Ferrante, who grew up in Flushing and now lives upstate, almost didn’t tell it. After his release in 2003 — he successfully appealed his own case — Ferrante moved to Massapequa and hoped to publish a 1,000-page novel set in the antebellum South, but a pal convinced him to write a memoir.

“When I got out, I didn’t want to think about jail,” he recalls, tucking into a steaming, oven-fresh knish. “I couldn’t even watch ‘The Sopranos.’ But my friend goes ‘Lou, you gotta give it to them; that’s what people like. Write whatever you want later.’” Ferrante acknowledges that mafia lore remains ever popular. He’s up front about why “the life” appealed to a working-class kid who didn’t have much direction. “It was a place to hang my hat,” he says of the camaraderie he found in his crew. (In “Unlocked” he writes, “An eighteen year old in the Midwest, searching for these same feelings, might join the army or marines.”) Readers will find plenty of action — the book opens with Ferrante sticking a gun into a truck driver’s mouth — but don’t expect much on John and “Junior” Gotti.

He may be done with mob, yet Ferrante still has connections from back in the day. He’s proud he never ratted anyone out, and though I press for specifics on the Dapper Don and his son, he clams up. Alluding to several other higher-ups he knows, Ferrante adds that he “didn’t want to offend anybody. I want to be able to come to Manhattan for the rest of my life.”

Still, Ferrante offers up many provocative opinions. He’s astonished that Sammy “the Bull” Gravano turned informant against the Gambinos but points out that the crackdown on the mob tested even the most hardened of wise guys. “I think the sentences are outrageous,” he says. “I was facing 125 years; I never killed anybody. Give me five and see if I turn my life around — give me a hundred next time.”

Waxing philosophical, Ferrante says his circumstances could be anybody’s: “I think we’re all the same — whatever I did, you’re capable of doing, and whatever you’ve done in your life, I’m capable of doing.”

For Ferrante, such insight is hard won. He tells me how the stern morality of Judaism gives him a vital perspective on his life. “I felt it,” he says of the Torah’s teachings. “I know if you screw up, you’re going to get punished. I suffered and know it’s true.” He keeps kosher at home, and doesn’t eat pork anymore. But that’s no problem — he knows a butcher out in Wantagh who does a nice kosher braciole.