Mr. Orta was born in San Antonio, Tex., one of 12 children. He spent more than a dozen years in the Air Force, loading aircraft during the Persian Gulf war of 1991 and was dispatched to Germany, Korea and Saudi Arabia. By the time he returned to the United States, his wife had left him, and he struggled with alcoholism and homelessness. He moved to San Francisco, and five years ago qualified for a program assisting chronically homeless veterans.

At dusk he leaves his apartment building, which is wedged between a popular brunch spot for tech workers and a cannabis shop in the heart of the Mission neighborhood. The smell of marijuana fills the vestibule. Walking up a steep hill lined with mature trees, he passes homes that could pass for works of art: Victorians, some with stained glass and elaborate cornices and moldings painted in a soft palette of pastels, ocher, celadon and teal. A virtual tour of the neighborhood on the Zillow site shows that homes valued at $3 million and above are the norm.

But Mr. Orta doesn’t look at the architecture. He walks the streets, slightly stooped, his eyes on the ground and a flashlight in his back pocket. His friends call him the Finder.

On the six times Mr. Orta went out with a reporter, he followed a variety of circuits, but usually ended up exploring his favorite alleys and a dumpster that has been bountiful. (The first rule of dumpster scavenging, he said, is to make sure there’s no raccoon or possum in there.) In March, the dumpster yielded a box of silver goblets, dishes and plates, as if someone had yanked a tablecloth from underneath a feast in some European chateau.

“How do you say it?” William Washington, one of Mr. Orta’s trash-picking colleagues, remarked one night. “One man’s trash is another man’s treasure.”

Mr. Orta’s other recent discoveries: phones, iPads, three wristwatches and bags of marijuana. (“I smoked it,” he said when asked how much he got for the pot.) In late August or September, as participants return from the annual Burning Man festival in the Nevada desert, Mr. Orta says he often finds abandoned bicycles covered in fine sand.