Late at night, David Clark wakes up and goes to the kitchen to choose from the boxes of cereal atop his refrigerator. He pours cold milk into the bowl and counts his blessings.

Toilet paper, which he keeps in abundant supply. Body wash that lathers up nicely. A machine to shampoo the rugs in his immaculate one-bedroom apartment.

“When I come in, I can sit right there on that couch and turn on the television,” said Clark, 57, pointing to the worn beige sofa. “Don’t have nobody telling me when to get up or go to sleep.”

Clark has lived in his apartment in Arlington County for the past two years, after 26 alcohol-soaked years on the streets, when he frequently slept under Key Bridge. He is one of close to 300 chronically homeless men and women whom Arlington has placed in housing since 2011, using a rigorously organized, all-hands-on-deck approach that experts say could also work in cities with much larger homeless populations. The county found housing for about 100 homeless families during the same four-year period.

“Arlington is not alone, but they’re on the leading edge,” said Jake Maguire, a spokesman for Community Solutions, an anti-homelessness group. “It shouldn’t be unusual. It’s startlingly simple.”

Clark says he’s happy for the comforts of a home — things like a comfy couch, a television, boxes of cereal — after spending years on the streets. (Katherine Frey/The Washington Post)

Arlington has a master spreadsheet that lists homeless individuals by name, drawing from an annual survey of people living on the streets and carefully cultivated contacts at food distribution sites, shelters and other places where the vulnerable gather. The spreadsheet includes whether the people want housing, what health problems they have, their income sources and anything that might help or hinder their search for a home.

Once a month, there is a meeting of a task force that includes advocates and specialists in physical and mental health, as well as county social service workers. One person takes responsibility for each name on the spreadsheet. They go line by line, brainstorming about which public and private treatment programs and funding can be tapped to help each homeless person.

The process ignores agency divisions. The official in charge of federal Section 8 housing vouchers, for example, isn’t allowed to disregard someone on the spreadsheet who doesn’t qualify. Neither can the employee who tracks veterans’ housing disregard a nonveteran. Those who specialize in families can’t ignore the mental health needs of single adults.

“Breaking down all our silos and focusing on individuals by name was a huge thing,” said Kathleen Sibert, executive director of the Arlington Street People’s Assistance Network (A-SPAN). “You have to find programs they fit into.”

Clark’s path to his apartment began when one of the A-SPAN workers who offer food, blankets or shower vouchers to homeless people on the street identified him as especially vulnerable. She persuaded him to enter a residential detox program, where he worked on sobering up and was prescribed medication for diabetes, neuropathy and other health problems.

Ayana Bellamy became Clark’s case manager. She helped him get a state identification card, using the address of the residential program. (In Virginia, a permanent address is required for a government-issued ID, which often is needed to apply for apartments. Obtaining an ID can be the hardest part of the process, Bellamy said, because, by definition, homeless people don’t have a fixed address.)

Clark had trained as a cook at D.C. Central Kitchen and worked in kitchens at the Ritz-Carlton and Hilton hotels. But his drinking and his health problems kept him from finding a job and housing on his own. “I used to drink to wake up, and drink to go to sleep,” Clark said.

Karen Booker, who was living at a women’s shelter when she drew attention, wipes away tears as she talks about her children in her apartment, which she found thanks to Arlington’s innovative efforts. (Katherine Frey/The Washington Post)

He already received Social Security disability insurance income. Bellamy helped him fill out paperwork to qualify for food stamps and a federal housing subsidy. But Clark was turned down when he applied for a one-bedroom apartment — because of decades-old credit problems and a long-ago criminal record. With Bellamy, he successfully appealed to the landlord. He moved in on Feb. 1, 2013.

“We set out to house the hardest people, and we’ve done that,” said Robert Sharpe, assistant director of Arlington County’s Department of Human Services. “Because we’re meeting monthly, people follow up.”

Arlington employs a “housing first” philosophy — clients don’t have to overcome addictions or mental illnesses before the county will help them find a place to live. Housing, their biggest problem, is fixed first. Then, other issues are addressed.

Social service officials say the rent subsidies and other assistance needed to house one chronically homeless person generally cost the county about $22,000 a year, compared with $45,000 for that person to bounce between shelters, jail and hospital emergency rooms — what usually happens when a person is living on the streets. Caseworkers pay close attention to the newly housed and step in when needed.

For example, Clark was tempted to go out drinking after he moved into his apartment. But Bellamy was there waiting for him — with paperwork and a U-Haul full of donated furniture. While they were moving him in, another truck arrived with a new bed — something the organization buys for all its clients.

Clark’s desire for a drink, he says, slipped away.

Arlington, like other jurisdictions in the region, does an annual census of its homeless population. This year’s count happened Wednesday night, though the numbers won’t be released until sometime in April.

In recent years, the county’s homeless tally has declined, dropping from 531 in 2010 to 451 two years later. It fell last year to 291, a surprisingly low number that may be attributable in part to the county’s all-out effort to house people like Clark, but almost certainly reflects some homeless people seeking shelter at friends’ homes on last year’s census date, because the weather was bitterly cold.

Of the 278 individuals and approximately 100 families housed by the county since 2011, about 95 percent remain in their homes or apartments, officials say. (The others have been evicted; jailed; found shelter with family or friends; or left the area.)

The District, which has thousands of homeless residents, won praise for adopting a “housing first” approach under former mayor Adrian Fenty (D). But the effort slowed under Fenty’s successor, Vincent Gray (D), when federal funding dried up. Newly inaugurated D.C. Mayor Muriel Bowser (D) has hired Laura Green Zeilinger, who directed the city’s former effort, to direct the Department of Human Services and help revive the approach.

Karen Booker, 49, found her apartment with Arlington’s help in 2012. She had survived a harrowing childhood in the District, including sexual abuse by a stepbrother, and spent years raising her siblings and half-siblings while struggling with mental illness. She held jobs sporadically: receptionist at Walter Reed Army Medical Center; personal-care aide at a nursing home; janitorial worker. A drug habit drew her into a descending spiral of petty crime, prostitution and jail. “I had to do some horrible stuff to stay alive,” she said.

Booker’s children, now grown, were raised by their father. She was living at a women’s shelter when her name made the spreadsheet. “She was ready for housing,” Bellamy said.

Previous evictions made it difficult to find a landlord who would take her. And she had an outstanding debt that she believed she could not pay. Bellamy found out the debt was $96, low enough for Booker to cover with funds from her Social Security Disability Insurance. Federal money for permanent supportive housing was available to subsidize rent at a new place.

Booker’s apartment is an oasis from her previous life. Bright sunshine streams through the mini-blinds in the living room that she’s turned into a bedroom, after deciding the actual bedroom was too small and dark. A stuffed tiger sits on a queen-sized bed. There are red artificial roses on a side table.

Like Clark, she has slipped at times, But, she says, she has been clean since the fall. She earned a certificate as a home health aide, and is looking for a job in that field. She is proud that she worked as a cashier at Nationals Park on New Year’s Day during the National Hockey League’s Winter Classic. She is in touch with her children every day.

And Booker is getting used to having some financial stability. When she got her electric bill recently, she was puzzled by a line at the bottom: $200, with a two-letter code next to it. So she called Bellamy. Together they figured out that the low-income energy assistance Bellamy had sought on her behalf had kicked in.

That CR code? Clark had never before seen a credit on one of her bills.