Still, as you watch her move from booth to booth, chatting up customers, you can’t help but think time has been kind to Ali. Her hair is gray, concealing hearing aids she adopted a couple of years ago, and her back has a slight curve, the standard markers of a body in its twilight. But her voice is strong, and she moves through her restaurant with an authority that belies her nine decades.

In the span of 12 minutes, Ali has learned that customers from Texas, Illinois, Arkansas and China have come to Washington to soak up the experience at a diner that is both time capsule and timeless. She agrees to spontaneous requests for photos but insists they be taken near a back wall that reads: “Ben’s Chili Bowl, Home of the Original Chili Half-Smoke.” Her marketing instincts remain rock solid.

Two women tell Ali they flew in from Chicago for a conference. They had already snapped photos of Ben’s facade, a vibrant, condiment-colored storefront that stands out among the traditional brick structures along historic U Street NW. They were digging into a turkey hot dog and a jumbo beef dog when Ali appeared at their table. “We leave tomorrow,” Barbara Swain tells Ali. “There was no way we were going to leave without coming here.”

“Thank you for coming,” Ali says. “Enjoy our beautiful city.”

The exchange lasted only three minutes. The memory for the diners may last a lifetime. They had just met one of Washington’s most recognizable, most beloved, most photographed and most self-effacing residents. They had met the woman who has served presidents, civil rights leaders, celluloid heroes, writers, rappers, radio disc jockeys, journalists, junkies, judges, homesick students, homeless souls, Democrats, Republicans, tourists, locals, and any and all who have braved the line that snakes out the door at 3 a.m. after the clubs and bars have called it a night.

They had met the woman whom many just call Mom.

Ben’s has an official historian. His name is Bernard Demczuk, a Baltimore native who holds a doctorate in African American history and culture and who was, for many years, a senior labor adviser to Marion Barry when he was mayor. Demczuk has just written a biography of Ali, whose subtitle is “The Matriarch of D.C.” The subject of the book does not like the honorific.

“I said, ‘Bernie, I am not the matriarch of D.C. I’m the matriarch of Ben’s Chili Bowl,’” she says during an interview.

Her youngest son, Nizam, has tried to convince his mom that the honorific is a reflection of how the city feels about her, not how she feels about the honorific. His words have had little sway.

The argument is occasionally a topic of conversation between Ali and Beverly Mohamed, who have known each other since the 1950s, part of an informal clique known as the Golden Girls, whose members have mostly passed away. Mohamed, four years younger than Ali, says she will remind Ali of all the homesick Howard University students who consider Ben’s their refuge from the pressures of a new city and academic life, and find somebody there who treats them like family.

“I said, ‘You don’t understand how important that is to people. And how many people have memories like that.’”

“Her hands are so far reaching. Her love is so far reaching,” Mohamed continues. “Nobody knows all about it. She’s definitely the matriarch of D.C.”

Almost everyone who has more than a passing relationship with Ali has a story about her kindness.

Mary “Smoki” Fraser remembers that her sister, three years her senior, took her to New York City as a high school graduation present and then sent her checks when Fraser started college. Rick Lee, the retired owner of another U Street institution, Lee’s Flower Shop, says he met Ali when he was 10 and she was a teller at Industrial Bank; whenever she saw the young Lee waiting in the bank’s long line, she would usher him to the front. Blair A. Ruble, the author of “Washington’s U Street: A Biography,” remembers that Ali bought copies of his book and gave them as Christmas gifts.

Ali’s random acts of kindness have been so frequent — and so quiet — that Fraser is hesitant to reveal many of them, lest someone take advantage of her sister. But Fraser says the generosity has gone beyond money. “It’s people who would call her and need some food, and she would take them food. They needed a ride to the doctor, and she would take them. They needed somebody just to talk to.”

The matriarch’s character was formed early in life, on a farm in rural Virginia, about 90 miles south of Washington. Ali was born Virginia Rollins in 1933, and in many ways, her formative years were preindustrial. She and her family drew water from a well, and Ali would read by oil lamps at night until her home was wired for electricity when she was around 7. The family grew commercial crops — wheat, corn and soybeans — but also had their own garden, fruit trees and animals raised for meat.

“The only things we needed from the store were things we didn’t grow: coffee, tea, sugar, salt and vanilla,” Ali says.

Ali’s parents, Alphonso “Boo” Rollins and Esther “Essie” Smith Rollins, were major influences on her life, especially her father. Part English and part Native American from the Rappahannock tribe, Boo Rollins set the rules on the farm, and lived by them. He taught Ali and her siblings the value of generosity. Fraser remembers that her father would visit an older couple in the area — sometimes twice a day in their later years. He would bring them fresh vegetables, eggs and milk. Boo Rollins firmly believed in the Golden Rule: Do unto others as you would have them do unto you.

But, Fraser adds, he also told his kids to “be strong when we needed to, when we needed to address an issue.”

Ali’s Black ancestors were on her mother’s side, as best as the family can determine, Fraser says. Despite her mixed heritage, Ali was deemed a person of color by the state. Based on the racist science of eugenics, the Racial Integrity Act of 1924 was the law in Virginia back then — it identified a White person as someone “who has no trace whatsoever of any blood other than Caucasian” — and because of it, Ali attended Black schools and churches. The family, Fraser says, was equally comfortable in Native American and Black communities.

“My sister has been able to float and be comfortable in many different situations and groups,” Fraser says. “She knows how to meet people regardless of their station in life.”

When the former Virginia Rollins moved to Washington in the early 1950s and fell in love with Ben Ali, a Trinidadian native of Indian descent, she would have a more direct encounter with intolerance. As Demczuk writes in his biography, the pastor at Virginia Ali’s church in Washington would not marry the couple because she was Christian and Ben was Muslim. “It’s against God’s will,” the pastor told Virginia Ali, according to Demczuk’s book. What’s more, Ben Ali’s mother, Khadija, objected to the marriage.

The couple would get married anyway in 1958, in a judge’s chamber. Virginia Ali then went to work developing a relationship with her mother-in-law. She again leaned on her father for advice. When Khadija was rude to her, Boo Rollins told his daughter, “Honey, don’t hold it against her. She doesn’t know you yet,” Virginia Ali recalls.

She has an ability to bring out the best in people, says her eldest son, Haidar, who goes by the nickname Sage. She even “won over my grandmother,” Sage says of Khadija. “In the end, she was Mom’s favorite.”

Ben’s Chili Bowl had been open less than two months when Virginia and Ben Ali tied the knot. Their budding business, much like the farm that she knew as a child, was situated in a self-contained community. A 1953 Supreme Court decision had prohibited segregation in D.C. public places, but the city remained largely splintered along racial lines in the late 1950s.

U Street was still a thriving Black neighborhood, with its own banks, barbers, lawyers, doctors, nightclubs, theaters, eateries and more. From behind the counter at Ben’s, Virginia, a girl who had picked farm vegetables a decade earlier, was now rubbing elbows with the greatest entertainers on what was known as Black Broadway: Count Basie, Dinah Washington, Lena Horne, Cab Calloway, Harry Belafonte and Nat King Cole.

Another sign of a divided city: Despite its growing prominence in the Black community, Ben’s Chili Bowl barely rated a mention in The Washington Post in the 1950s and 1960s, aside from classified ads looking for a “counter girl.” The first editorial mention of Ben’s came in a 1969 item, which reported that a delivery driver had been held up outside the “carry-out restaurant.” The second was a 1971 story about the District’s new environmental services chief, who made unannounced visits to various establishments to respond to charges “of questionable restaurant hygiene.”

Nowhere in the paper’s archives are contemporaneous accounts about how Ben’s, and its gutsy owners, had survived the riots that followed Martin Luther King Jr.’s assassination in 1968, and the many tumultuous years after. Those stories would come much later.

The short answer for how Ben’s made it through those troubled years, Ali says, is goodwill. She and her husband had built up a lot of it in their first decade. Ben’s Formica countertops were available year-round for everyone who entered, whether construction workers on lunch break or civil rights activists looking for something to eat between planning sessions for the March on Washington. King was known to her not just as a calm and confident leader, comfortable in any situation, but as a diner who loved Ben’s chili cheeseburgers.

Virginia and Ben were never activists themselves, she says, but they supported the civil rights movement with checks and occasionally with their presence. They left their business in the hands of employees on Aug. 28, 1963, so they could attend the March on Washington on the National Mall, where King delivered his indelible “I have a dream” speech.

“We were so inspired,” she recalls. “We came away with, ‘Oh, yeah, change is going to come.’”

In the years that followed, change did come: President Lyndon Johnson signed into law the Civil Rights Acts of 1964 and 1968, which prohibited discrimination in all facets of American life, freeing Black residents to live and work in other parts of town. These laws, combined with the 1968 riots, would bring sweeping changes to U Street, too, hollowing out a once-proud community and transforming it into a haven for drug dealers, such as Roland Walter Brown, a guy known on the streets as Rabbit.

“He was a bad little guy,” remembers Rabbit’s brother Rhozier “Roach” Brown, 79, a former Marion Barry aide who has spent 30 years of his life in prison. But Rabbit also admired the Ali family and their many good deeds in the community, the brother said, so “he put the word out: that don’t nobody bother” the family or their business. Roach Brown says his brother was so respected, and so feared, that no one dared violate his edict.

This may help explain why Ali, as she says, could walk cash receipts to the bank, down a street populated with desperate people, and no one would bother her. It may also help explain a statistic often repeated about Ben’s: It has never been robbed in its 65 years in operation. If you ask her about the robbery-free streak, she will take her hand and knock on your head, then her own, as if both were made of wood.

The streak is hard to confirm. To check records dating back to 1958, the D.C. police needed a Freedom of Information Act request, which is still pending.

But Mohamed, Ali’s longtime friend, remembers one break-in at Ben’s, though she doesn’t remember the date. One U Street denizen, Mohamed recalls, would regularly visit Ben’s late in the evening, and Ali would treat him to a half-smoke. One night, this guy, clearly not in his right mind, arrived at Ben’s after it closed. But there was a single half-smoke lying on the grill by the window. He was convinced that Ali, the guardian angel of U Street, had left it just for him. So he smashed the window to grab it, Mohamed says.

“How do you make someone believe that you care that much about them?” Mohamed wonders.

In December, Ali celebrated her 90th birthday at the Lincoln Theatre on U Street, where some of the biggest names in politics, entertainment and business gathered to pay tribute. They included Sheila Johnson, co-founder of BET; DJ Donnie Simpson; and D.C. Mayor Muriel E. Bowser. Washington Wizards guard Jordan Poole presented Ali with her own bobblehead, the first woman to be honored with a figurine in team history. Steve Harvey, the television host and comedian, passed along birthday greetings via video, and Barack and Michelle Obama sent a letter.

“Thank you for all you’ve done to create a space where kindness, community and good eating have flourished for so long,” said chef Alexander Smalls, co-host for the party, reading from the Obama letter.

Yet, here’s the thing about Ali’s brand of community: It’s not exclusive. It does not cater just to the famous and the powerful, even if many of those people have their photos on the walls at Ben’s on U Street. Ali’s type of community includes employees, such as Maria Guadalupe Martinez, a prep cook who has worked at Ben’s for 34 years, and the late Bernadette “Peaches” Halton, the only person outside the Ali family who knew the diner’s famous chili recipe. Ali’s community understands that the justice system is not always just to people of color. As such, Ben’s is a space where people are given second — or third — chances.

Just ask Roach Brown, a convicted murderer whose sentence was commuted by President Gerald Ford in 1975. Twelve years later, Brown was sentenced to two consecutive prison terms for selling cocaine and embezzling from a charity. He says he was serving his time quietly when out of the blue, a note arrived from Ali, whom he had known and respected for years. It included a $50 money order.

“When I saw the 50, I just started crying,” says Brown, who hosts a live radio show on the first Tuesday of every month at Ben’s. “This lady is a special human being.”

Ali’s loyalty to community and friends has been put to the test multiple times over the decades. From 1986 to 1991, construction of the Metro Green Line tore up U Street and the sidewalks around Ben’s, dropping sales to as little as $100 a day while nearly quadrupling the family’s tax burden. “I am surprised we are still open,” Ali told a Post reporter in 1991, days before the Green Line finally opened. The business survived largely because of the bakery and ice cream shop that Ben’s opened in the nearby Franklin D. Reeves Municipal Building, says Ali’s son Kamal, who ran the bakery for years.

But perhaps her biggest challenge came in the mid-2010s as magazines and newspapers began detailing dozens of cases in which actor and comedian Bill Cosby was accused of rape and sexual harassment. Cosby had been a loyal patron of Ben’s since the 1950s when he was a hospital corpsman with the U.S. Navy. As Cosby’s star rose, he brought Ben’s along for the ride. He held a national news conference at Ben’s in 1985 to address criticisms that “The Cosby Show,” then the No. 1 program in the land, did not present an accurate portrait of Black life in America.

“That’s when we became big in the press,” says Nizam. “And then all of a sudden we’re on the news all the time.”

Cosby sang Ben’s praises on “The Oprah Winfrey Show.” He appeared at the restaurant’s anniversary celebrations. He presented the award when Ben and Virginia Ali were inducted into the D.C. Hall of Fame in 2011. He made special detours to Ben’s whenever he was in Washington. But his relationship with Ben’s seemed to unravel with each allegation — and the increasing calls for the Ali family to take down photos of Cosby and remove him from the famous mural on an alley wall.

Breaking all ties with a family friend — one who helped make Ben’s famous around the country — would not seem to fit the pattern of Ali’s life. But Cosby is one topic that she will not discuss publicly. It’s not clear whether she remains in contact with Cosby personally, but all traces of the fallen star have been removed from Ben’s, including a sign that once said that only Cosby eats free. (Barack Obama’s name was added to the sign after he made a surprise appearance ahead of his 2009 inauguration.)

“We let time work it out, let the court case go on,” says Kamal. “The whole thing was a hot mess. We just chilled and took a back seat to it, respectfully. At the time, the mural became worn out, and we decided to do a survey for who people wanted on the mural. We let the public decide that.”

The Cosby mess led to another significant change at Ben’s Chili Bowl, Nizam says. It made Ali the undisputed face of the business.

These days, Ali assumes the role of ambassador at Ben’s, though her sons say she still exercises some oversight, even from her home in the northern tip of Washington, near the Maryland border. Ali suggests that her frequent presence at Ben’s is as much a stimulation for her as it is for the diners.

“If I’m at home now at my age and I don’t feel up to par, all I have to do is take a shower, put on something and come in this door,” she says. “I’m energized by the people.”

Ben Ali died in 2009, and Virginia Ali has ceded control of the business to her sons and their wives. Job descriptions are often fluid among the second-generation operators, but Sage leads the charge on franchising Ben’s beyond its two storefronts in Washington and its outposts at Reagan National Airport, the Walter E. Washington Convention Center and Nationals Park. Sage’s wife, Vida, and Nizam handle the retail side, which includes a line of half-smokes and chili at Giant grocery stores. Kamal handles business operations, while his wife, Sonya, oversees e-commerce, merchandising and catering.

The matriarch has veto power over all decisions but says she rarely exercises it. At the moment, though, she’s a bit worried about an upcoming renovation, which will close the original Ben’s for a couple of months to upgrade their 114-year-old building’s aging infrastructure. No date has been set yet for the work.

She has told the family, “I want it to look the same way it looks now,” she says. “Just fix everything.”

Change has been the one constant inside the original Ben’s, even if a large part of the diner’s attraction is its ability to evoke a time before people communicated largely through a device in their hands. Ali has adapted to all the changes that life has thrown her way, but she’s skeptical about the technology that keeps people separate.

“For the most part, the country has grown, and I think I have lived in the best times in this country, because of the growth I’ve seen,” Ali says. “I wonder where we’re going from here, and I wonder because I thought relationships and people were so precious. I think that’s kind of going down the drain.”