When Madam C.J. Walker first rolled into Irvington, New York, in her high-powered motorcar, the 49-year-old beauty magnate caused tongues to wag. “Impossible,” the Hudson River town’s residents told the New York Times when they heard this black woman was building an Italianate manse right on the main road. “No woman of her race could afford such a place.”

Oh, but she could.

It was 1917, and Madam Walker was America’s first female self-made millionaire, a former washwoman born from slaves who had made her fortune launching a line of hair-care products. The Irvington property, dubbed Villa Lewaro, was the pinnacle of her achievements: a 34-room Italianate manse in a neighborhood that was also home to Rockefellers and Astors.

“It was symbolic for her,” A’Lelia Bundles, Walker’s great-great-granddaughter, told The Post. “For her to buy property in one of the wealthiest communities in America and then build this home, one generation out of slavery, it was her American Dream.”

One hundred years later, Madam C.J. Walker is enjoying a bit of a comeback. Sundial Brands has recently launched a new line of Madam C.J. Walker de-frizzing products, while Octavia Spencer — nominated for an Oscar this year for her supporting turn in “Hidden Figures” — has signed on to produce and star in a TV series based on Bundles’ biography on her great-great grandmother.

But while Villa Lewaro has been granted Landmark status, preservationists are concerned about the magnificent home’s future.

“Even though it’s a National Historic Landmark, there’s no oversight or review to stop an external agency to propose changes to the building,” said Brent Leggs, a senior field officer at the National Trust for Historic Preservation. Significantly altering it or demolishing it could be a blow to Walker’s achievements, which is why the Trust is working with the Doleys to procure an easement that will ensure the Villa’s long-term protection.

“It’s one of the most important women’s history sites — and African-American history sites — in the country,” said Leggs. “It’s absolutely crucial to find the next steward who can carry on its legacy.”

Madame C.J. Walker was born Sarah Breedlove in 1867 in Delta, La., on the plantation where her parents and older siblings had been enslaved. Orphaned at 7, Sarah was sent to live with her sister and brother-in-law, who forced the child to work the fields and wash clothes in order to earn her keep. She married at 14 — to escape her sibling’s house — but by 20 was a widow and single mother in Vicksburg, Miss. (No record exists of his death, and Madam only spoke of it in vague terms, but several journalists later theorized he was killed during a race riot or lynched.)

Walker once told an interviewer that she’d had only three months of formal education. It wasn’t until Sarah and her 3-year-old daughter Lelia moved to St. Louis, where her three brothers had a barber shop, in 1889, that she learned to read. The African Methodist Episcopal church in town provided educational resources to newcomers, and also boasted a congregation that included many learned, successful black men and women.

“I think that’s when she began to envision herself as something other than an uneducated washerwoman,” Bundles said.

Then fate intervened. Right on the heels of a failed second marriage, Sarah’s hair began to fall out as a result of damage caused by products featuring lye and other harsh materials. While Madam later claimed that the recipe for her “Wonderful Hair Grower” came to her in a dream, in truth, a local chemist showed her how she could mix her own conditioning and healing formula using sulfur, beeswax and a bit of fragrance. In 1906 — taking the name of her new husband, newspaper ad man Charles Joseph Walker — she launched Madam C.J. Walker, one of the first hair-straightening products marketed specifically to African-American women.

‘For her to buy property in one of the wealthiest communities in America and then build this home, one generation out of slavery, it was her American Dream.’

She also developed a large network of empowered black women across the country to sell her wares.

“If she had just tried to sell a formula door-to-door on her own she would have been mildly successful,” said Bundles. “But her genius was in her ability to market and to motivate other women.” Walker had made $1.25 a week washing clothes; a decade later, her sales agents could earn anywhere between $5 and $15 a day.

In 1916, Walker’s daughter Lelia, now 31 and helping her mother with the business, had settled in Harlem, where she had noticed a sharp increase in demand for Walker’s products. So she encouraged the now-divorced Madam to join her. There, the mother and daughter fraternized with journalists like Ida B. Wells and W.E.B. DuBois, hosted salons featuring writers like Langston Hughes and Zora Neale Hurston and took on leadership roles in the NAACP’s local chapter. Madam was by then a millionaire, and the beautiful, 6-foot-tall Lelia was dubbed the “goddess of the Harlem Renaissance.” Local celebrities, the two lived in a spectacular townhouse on 136th and Lenox Avenue.

In 1917, Walker began scouting for a weekend estate where she could entertain. A real estate agent suggested she look at a 3-acre plot of land in Irvington, an area known for its mansions and exclusivity. “He said, ‘This is absolutely where you want to be to make a statement,’ ” Bundles said.

Walker hired the state’s first licensed black architect Vertner Tandy, who had overseen the building of her four-story Harlem townhouse, to design her new mansion. He came up with a $250,000 three-story stucco villa with a tiered terrace that led to a swimming pool. The interior, with its multiple windows, high ceilings and marble floor, borrowed heavily from Italian Renaissance architecture. Though Madam never learned to play a musical instrument, that didn’t stop her from installing an $25,000 Estey organ — an astronomical cost at the time — in the home’s ornate music room, where dancer Isadora Duncan, Broadway composer John Rosamond Johnson and Frederick Douglass’ grandson, the violinist Joseph Douglass, would all perform.

“Estey [the esteemed organ makers] was very reticent about sending employees here to build this organ when they found out that Madam Walker was a woman of color,” said Helena Doley, who has lived in the house for almost 25 years. “They questioned how could this woman know of such things, and how does she pay for such things, but in the end they did it.”

Sadly, Walker only got to live in her new estate for a year before she died due to kidney failure, at the age of 51.

Lelia took over the house after her mother’s death, using it mainly as a weekend party palace. It was during one of her bashes that the famous Italian tenor Enrico Caruso gave the chateau the name of Villa Lewaro, after Lelia Walker Robinson, her married name. She also became president of her mother’s beauty company, even hosting Madam C.J. Walker’s employees at the villa for annual retreats.

Walker had stipulated in her will that after Lelia’s death the house should go to the NAACP, but the property taxes and the costs associated with a house of that size were too much for the organization to shoulder and the house was sold in 1932. It then became a retirement home for 40 years.

“Thankfully, [the retirement home owner] did not make a lot of alterations to the building,” Leggs, of the Historic Trust, said. But they didn’t necessarily keep up the home either.

“I cried,” said Doley, remembering the first time she set foot on the property, which her husband, the former US ambassador to the African Bank Development Fund, was committed to saving. “The front portico was taking on water like a swimming pool. The plumbing didn’t work — forget about any modern conveniences. The house was overridden with rats, with insects of all kinds. There were squirrels in the wall; the chimney was wide open, so animals were getting in.”

And while the original lighting fixtures, moldings and architectural elements remained, almost none of Madam’s furnishings survived. “Lelia was not as astute about the business as her mom,” said Doley. While she managed to keep the company afloat, the Depression meant that sales were down, and Lelia auctioned off many of Villa Lewaro’s treasures — Walker’s collection of rare books, her prized piano and her bone china from England were sold for pittance. The Estey organ is still in place.

The Doleys upgraded the house’s mechanical, electrical, heating and plumbing systems. They reconstructed the terra cotta roof with materials from the original manufacturer and restored the wall paintings in the dining and music rooms.

“It is this enormous responsibility,” said Doley, who added that she was at first resistant to moving into the Villa with her husband and then-teenage son. “How does one live in a house like this, and how does one share it with the community and still have a life, a personal life? It’s been overwhelming, and it took years to accept it.”

Now, Doley loves mansion, where she’s hosted family members’ weddings and celebrated her 60th birthday, but she and her husband, are ready to downsize. The couple worked with the National Trust to have the property designated as a National Treasure in 2014. And now the National Trust for Historic Preservation is trying to find new uses for the space, such as a spa and salon, a corporate retreat center, an events space or a private residence. The two parties are finalizing an agreement to protect Villa Lewaro in perpetuity while the Trust seeks options to preserve the house as a public monument to Walker’s legacy.

“We would hope that whatever is decided that it’s open to the larger community, so that they can come and appreciate her and what she’s done,” said Doley. “African-Americans have been contributing to the culture and growth and betterment of the country for a long time. It’s just that we’ve been written out of history books.”