Sandra Galuten went from living in a $6 million, 15,000-square-foot mansion with marble floors and a cocktail lounge to a room in a Bronx hotel.

For decades, Galuten, 80, and her entrepreneur husband, Jerry, delighted in the 17-room Riverdale manor they lovingly renovated — a house originally built in 1928 by a kooky cult leader for the second coming of Jesus.

The house was constructed by Genevieve Ludlow Griscom, a wealthy businessman’s wife who belonged to the Outer Court of the Order of the Living Christ.

She and the other members never lived in the house meant for their messiah but regularly dusted it and polished the floors in anticipation of his return. Griscom would enter for an hour every day to play a pipe organ.

Jesus never came, and Griscom died in 1958. The property was given to the Archdiocese of New York, then nearby Manhattan College. It lay derelict for more than a decade before it was bought by the Galutens in 1987 for, Sandra says, “practically nothing.”

They rehabbed the mansion, located atop the city’s second highest peak. It featured a glass-ceilinged sun room, and a game room with sconces that once belonged to Clark Gable.

“It was a wonderful house because it flowed. It had 14-foot ceilings, a lot of chandeliers from The Plaza hotel, and I did the decorating,” Galuten boasted.

But clouds began to gather after Jerry Galuten’s death in 2007. With Social Security her sole income, Sandra claims, she fell behind on her city real-estate taxes.

She put the estate, at 360 W. 253rd St., up for sale. It was on and off the market for eight years and sold in January 2017. Its price tag plummeted from an original $15 million in 2009 to a final sale price of $6.25 million.

Galuten wound up with a “mere” $357,000, according to a lawsuit in which she accuses her broker of fraud.

“You learn in life to roll with the punches,” she told The Post. “I’m selling off my antiques and art.”

Galuten now lives in a chain-hotel with her dog, Coco. She asked to keep its location private.

But the former marketing executive cheerfully recalled days of charity events and “fashion shoots” in her former home with the likes of photographer Steven Meisel and actress Susan Lucci.

“It’s tragic that she has gone from a mansion to living in a hotel, essentially from hand to mouth,” said attorney Dennis Houdek, who filed the Manhattan Supreme Court suit.

In May 2013, Galuten was introduced to broker Robert Perl, who touted his real-estate acumen as a “panacea,” the suit says.

Perl “convinced her to sign over total control of the property,” Houdek claimed.

“Once he had total control, he failed to even list the property for sale and instead further convinced her to take out two separate mortgages on the property.”

The “onerous terms” of the two mortgages “ultimately forced her into a distressed sale,” he said.

Perl received $760,000 at the 2017 closing, his lawyer said.

One of the mortgage holders received more than $4.7 million, the suit says, and Galuten ended up with less than 6 percent of the purchase price.

“We allege that Perl exploited the elderly Galuten,” Houdek said.

Perl called the suit “completely false” and with “no basis in fact.”

“The vast majority of the money I received at closing was a return on the investment I made in the property,” he said. “The funds were used to obtain the deed and other expenses such as maintenance and insurance for a period of time.”

As for Galuten’s claim that she was “duped” and that the house should have sold for at least $10 million, Perl said, “She plays on everyone’s heartstrings . . . She’s played that song for decades.”