Just after 4:40 a.m., James Sampaga started unstacking chairs and rearranging tables, thunking furniture against the floor so loudly that employees in the next building could hear the ruckus.

When he finished, the cafeteria of Glide Memorial United Methodist Church grew quiet, aside from the hum of commercial-grade refrigerators stuffed with 200 hams and 300 turkeys. Here, in the early hours of Christmas Day, before San Francisco’s homeless and low-income residents began lining up for a tray of hot food, before 500 volunteers arrived to serve them, Sampaga, 51, was alone.

He was once on the receiving end of the line.

Shortly after moving to the Tenderloin from Salinas, Sampaga worked at a restaurant on Pier 39, but his paycheck barely paid the bills. He was just another man in the city, hungry, unable to afford a holiday meal. Accepting a hand-out hit his pride, but it was better than an empty stomach. That was more than a decade ago.

Sampaga now works full-time at Glide as a supervisor, helping to run the church’s annual Christmas meal program. Thirteen years on, he still possesses the same sympathy and empathy others once showed him.

As 10 a.m. neared, and light filled the cafeteria windows, Sampaga smoothed the black tablecloths and double-checked the volunteer shift schedule. Tattoos snaked under his plastic gloves, and he shouted above the growing clamor. A ring of keys on a chain hung from his pocket, tinkling like bells with each step. He was a blur of movement, zipping from the kitchen to the dining room, pausing only to guide a petite woman — one of the first to receive her holiday meal — up some steps.

“Steady, mama, steady!”

Change started with a bet Sampaga made himself. He had to see if he could make it a whole paycheck, then 30 days, then six months, without drugs. He won’t say which drugs, because that seems too personal.

“Don’t you think? Maybe too personal,” he said. “When you’re young and wild, living on nothing and doing drugs is romantic. But I’m 51. I like stability now. With a destructive lifestyle, you can’t have that. To move forward, you have to change.”

He paused: “Hold on — I know that guy, lemme say hi.”

The bet worked. Sampaga now lives in a one-bedroom apartment in Castro Valley with his fiancee. She has an engagement ring. He has a sport utility vehicle. Together, they have a mutt named Mason, who goes to day care while they’re at work, the kind that serves doggie ice cream and throws doggie birthday parties. Sampaga considers it a miracle. Even he didn’t go to day care as a child.

Sampaga has self-respect now. He values his life too much to take drugs. He realizes, even though he’ll probably never get the whole pie, he can definitely get a bigger piece, so he works harder. He’s studying to get his high school diploma and stands just 65 credits away, even though he can’t really remember algebra.

“Having to come here and eat was hard,” Sampaga said. “For someone to put down their pride and let someone else feed them and help them, that was tough. I know a lot of them feel this way. I’ve been lucky enough to get through it, and hopefully some of these cats will, too.”

He adjusted his black and purple Lakers cap and pointed to an open seat.

“Sir! Youngster! Hey, youngster! There’s an open chair right here.”

Another five people went through the line. They carried bags filled with Tupperware — maybe they could stretch the meal two or three days. But if they ate the entire entree, they could go outside and get a second red paper ticket for a second meal. Behind the glass guard, volunteers heaped mashed yams, cranberry sauce and vegetables onto the trays.

Anthony Balunsat, 64, wearing a Santa Claus cap fringed with white fur and a red raincoat, received his meal and spied the steaming mashed yams. It wasn’t the kind of food he could cook in his single-room occupancy apartment, which only has a hot plate and a small fridge. He never imagined holidays like this when he was a child, growing up in the Mission.

Back then, Balunsat would bring his new toys outside to show the neighbor kids and they’d play on the sidewalk together. That was a different time. Now he lives on a fixed income and tries to survive off social security.

On this holiday, Glide helped fill in one of the gaps.

“I just wanted some food to eat,” Balunsat said. “I’ve been coming here for years. After this, I’ll go to St. Anthony’s, because they serve food, too. I can make this last awhile.”

Sampaga patted him on the shoulder. He knows the feeling.

Around 11:30 a.m., more people rushed past and the line momentarily dissipated. Sampaga called out over the cacophony of conversation and clattering forks.

“I have my next shift, volunteers,” he said. “So, you’re free to go. Come back on a Tuesday in February when people aren’t feeling the love.”

Sampaga gave a round of high fives and fist bumps, then turned back to work. More hungry people were waiting.

Lizzie Johnson is a San Francisco Chronicle staff writer. Email: ljohnson@sfchronicle.com Twitter: @LizzieJohnsonnn