SAN FRANCISCO — As San Francisco’s Board of Supervisors prepared to vote Tuesday on an ordinance forbidding city agencies to use facial recognition technology, some proponents of the measure were uncertain if they had the necessary support. Two of the legislators who were for it had called in sick.
But Brian Hofer, a paralegal who had drafted the ordinance, seemed unfazed. Sitting in the back of a chamber in City Hall, he wrote and rewrote a draft of a post for Twitter in which he would proclaim victory after the ban passed.
Mr. Hofer, 41, had reason to feel confident. Over the past five years, he has drafted 26 privacy laws for cities and counties in California. All were approved, 23 unanimously. And he had seen enough of the machinations of decision-making to be certain that this one would go through.
“He’s just omnipresent and very effective,” said Lee Hepner, a legislative aide to Aaron Peskin, the city supervisor who sponsored the facial recognition ban. “He’s great at bringing down the volume and making it a level-headed conversation.”
Mr. Hofer is little known outside California, but his anti-surveillance measures have been making waves in the state.
He successfully pressed the Northern California cities of Richmond and Berkeley, which have sanctuary policies, to end their contracts with tech companies like Amazon and Vigilant Solutions that do business with Immigration and Customs Enforcement. In Santa Clara County, in Oakland and elsewhere, he has secured transparency laws around surveillance technology.
His campaigns are just beginning. In Berkeley and Oakland, Mr. Hofer is pushing for more facial recognition bans. He has two additional privacy proposals winding their way through the state’s legislative process, focused on reining in surveillance technology. And he is establishing a nonprofit, Secure Justice, that will grapple with technology issues.
“My primary concern is when the state abuses its power, and because of the age we live in, it’s probably going to occur through technology and data mining,” Mr. Hofer said. “That’s where I see the most potential harm occurring. So I just wanted to jump right in.”
[Get the Bits newsletter for the latest from Silicon Valley and the technology industry.]
From his earliest days, Mr. Hofer displayed his gadfly tendencies. He was raised in Weed, a small Northern California town where the politics lean libertarian and where the Jefferson movement, which proposes breaking off the northernmost bit of California and a slice of southern Oregon to form a new state, has long held sway.
Mr. Hofer moved to the Bay Area in the late 1990s and studied economics at the University of California, Berkeley, and law at the University of San Francisco, though he delayed taking the bar exam when he began focusing on anti-surveillance activism. He supported himself by working as a paralegal and now lives in Oakland with his younger brother, who is completing a degree at Berkeley.
Mr. Hofer started to hold technology accountable in 2014 when he heard about a new surveillance system in Oakland. The system, the Domain Awareness Center, was designed to aggregate data from security cameras, license plate readers, gunshot detectors and other technology.
“I had never walked into City Hall for any reason,” he recalled. But Mr. Hofer soon joined a group of privacy advocates and started attending City Council meetings to voice his objections to the intrusiveness of the system.
The Oakland project was scaled back after protests — and Mr. Hofer was hooked. He began seeking out other ways to oppose surveillance initiatives.
“It’s forcing transparency into the conversation,” he said.
Mr. Hofer took on a range of anti-surveillance initiatives. He began drafting legislation that would force cities to be transparent about the surveillance systems they deployed, or to cut technological ties with ICE. He said he did not consider himself anti-tech and was just trying to prevent the authorities from abusing the power of technology.
The facial recognition bans are Mr. Hofer’s latest cause, partly because he sees an opportunity to cut off the technology before it becomes widespread and entrenched, he said.
“On balance, it’s such a dramatic shift in power that for the first time, aggressively, I want to say this is where we draw the line,” said Mr. Hofer, who worked with the American Civil Liberties Union and others to push the San Francisco ordinance through.
Last Thanksgiving, Mr. Hofer experienced the surveillance technology he has been examining firsthand. Police officers in Contra Costa County, using an automated license plate reader tool, pulled him over and accused him of stealing the rental car he was driving. Mr. Hofer said he had recognized the tool — it was made by Vigilant Solutions, a target of his sanctuary city ordinances.
“It showed me the real-world consequences of these sometimes speculative, hypothetical arguments that I’ve been making,” he said.
Eventually, the officers realized that the car had been stolen months earlier and that, when it was recovered, its plates were not removed from a list of stolen vehicles, Mr. Hofer said. He was released and is suing the Contra Costa County sheriff’s department, claiming civil rights violations.
On Tuesday, Catherine Stefani was the lone supervisor to vote against the ban, which passed 8 to 1. The legislation was “well intentioned” but required more work before it could be put into effect, she said. She worried that city departments would need to hire new staff to manage the transparency requirements and that the ordinance would create budget problems.
After the vote, Mr. Hofer and other supporters huddled in the hallway to debrief. He sent his victory tweet, crediting Mr. Peskin for championing the ban and noting that it was the first of its kind.
Matt Cagle, an attorney with the A.C.L.U. who worked with Mr. Hofer on the ordinance, said he had already received phone calls from regulators across the country who were curious about it.
“The desire not to be tracked when you walk down the street or watch-listed by a secret algorithm, these are shared values across the United States,” Mr. Cagle said. “We fully expect this vote and this ordinance to inspire other communities to take control of these important decisions.”
A few hours after the vote, Mr. Hofer was in Oakland. There, the City Council’s public safety committee was expected to debate one of his sanctuary ordinances, which would prohibit the city from contracting with tech companies that do business or share data with ICE.