One of Mike Hennessey's most enduring memories - as it is for anyone who was there - is of the Sex Pistols' final concert. It was at the now nonexistent Winterland ice skating arena at Post and Steiner streets, on Jan. 14, 1978. A young lawyer at the time - in fact the only lawyer in a grants-funded county jail legal assistance program - Hennessey dragged his then girlfriend, now wife, Beverly, to the show.

"I told her we had to see this band," he remembers. "She thought they were just atrocious. I thought they were great."

Mike Hennessey, sheriff of the county of San Francisco and a man with a lifelong passion for jail reform, is a punk rocker. He'll take Green Day any day over REM, the Pistols over just about anyone. If this particular penchant for punk had become public knowledge, there's a chance it might have affected his recent election. He might have gotten 79 percent of the vote instead of his overwhelming 80 percent. Or, this being San Francisco after all, he may have gotten 85 percent of the vote.

Hennessey is arguably the most popular elected official in The City. Certainly no one approaches his margin of victory. There have been times since he first won his job in 1979 that no one has dared run against him. Hennessey thinks he understands why the voters love him so, even if his policies buck the current wave toward increased punishment for criminals.

"People want me to run their jails safely and professionally, make sure that the bad guys don't escape and that the system is not brutal," he says. "But I think the reason I have such wide support is that I try to take law enforcement beyond that. I've developed job programs and education programs and substance abuse programs. The people of San Francisco, this being a liberal and progressive city, respond to that form of innovation."

Sitting in his temporary quarters in an ugly, nondescript building on Folsom Street, Hennessey looks very much like what he is: the Irish son of a small-town Iowa doctor. His gaze is direct, he doesn't mince words and there are none of the frustrating verbal end-arounds - the specialty of most other politicians. You ask Mike Hennessey a question, he thinks about it and gives you an answer. A novel concept for an elected official.

Capturing 80 percent of the vote is, in Hennessey's own words, "unheard of." But San Francisco, as everyone knows by now, is a bit different.

"We voted against the death penalty, we voted against Prop. 187, we voted to keep Rose Bird, we voted against "Three strikes and you're out,' " Hennessey recites.

"We have a very well-educated population, and we also have a population made up of a majority of minority citizens. They have been discriminated against in life and they view the criminal justice system as a vehicle of that discrimination in many ways. So our city looks to alternatives to incarceration, if there are any that are reasonable and safe for the community."

Hennessey is so popular that other politicians, predictably, line up in hopes of winning his backing. In the bitter district attorney's runoff, perhaps the toughest race of the year, both candidates were openly courting Hennessey before he eventually gave his endorsement to law school classmate Bill Fazio. Even so, neither has a disparaging remark about the sheriff.

"I think his popularity proves that San Francisco's liberal tradition is alive and well," said liberal Terrance Hallinan. "I think San Francisco voters respond to compassion and commitment."

Fazio's statement was equally self-promoting, as can be expected just before a runoff. "I think he brings innovation to the law enforcement process, which is exactly what I plan to do as district attorney. I hope his popularity proves that San Francisco has intelligent voters, because intelligent voters look at a candidate's entire record." Among Hennessey's innovations for inmates are 12-step meetings, tutoring, plus horticulture and tree-planting programs. The educational advances are the ones he's most proud of.

"We had 61 people get their GED last year - get their high school degree in jail," he says. "On the one hand, that's a pathetic statement that people would have to get their high school degree in jail. On the other hand it's a very inspiring thing. We had another 600 people that passed part of the five-part exam, that's 600 people motivated enough to study and pass part of the test. We tell people in the community about that and they invariably say, "We didn't realize you were doing that.' There are so many stereotypes about prisons being brutal animal factories churning out animals that if people see an alternative that might work they are very happy to support it."

Even with all the efforts made toward rehabilitation, there is about a 60 to 70 percent recidivism rate for prisoners, a figure that Hennessey acknowledges is frustrating, though not debilitating.

"You can't throw up your hands. We deal with tens of thousands of people. You can't expect to change them all, but if you change a few, you're doing a pretty good job. You wish you could change people's lives, but you can't change everybody's or even very many lives. But you can definitely create the opportunity for someone to change their own life."

During Hennessey's tenure, the jail population has grown to 2,100 inmates. A new jail has been built and opened next to the old jail at 850 Bryant St., a $50 million structure that Hennessey says he was "singularly responsible for," as far as acquiring funding. The jail has been criticized as being too plush, overly designed, not harsh enough. Hennessey quickly dismisses such claims.

"The jail is designed primarily for safety and security," he says. "No one should escape and no one should be in any danger while they are serving their sentence. The inside of the jail is designed for more direct supervision, which cuts down on inmate violence.

"As for the exterior of the building," he continues,

"that was an application of public art money. We didn't want to just erect a statue outside of some monstrosity. There's no reason why a $50 million building has to be ugly. People drive by it every day. And it's no more plush than the Marin jail, or the Santa Clara jail. It's the way jails are being built these days. There's no reason to make it look like a dungeon."

As for the prisoners, during Hennessey's tenure, they have, surprisingly, been getting a bit older, not younger.

"Two years ago we had a lot more drive-by shootings and we're kind of in a down cycle lately, so the population is actually a bit older," he says. "What really stands out about the population is that of the 2,100 inmates, 30 percent are there for drug offenses. I'm not even talking about burglary or car boosting or any of the other crimes committed to get money for drugs. I'm talking strictly about possession, sale and transportation. There are something like 800 or 900 people in there for drugs."

Typically, a politician with Hennessey's popularity would be ravenously viewing the next rung up the ladder, anxious to cash in before the fickle public finds another favorite. Not so with Hennessey, although he confesses that he is not immune to temptation.

"I suppose early on, when I first was elected and found myself to be popular, I probably thought I'd like to be mayor someday. But as I've been in politics longer I find myself less interested in any other type of office," he says. "I'm more interested in implementing ideas than in creating legislation. I didn't run for this office to get into politics, I ran to do something about the jail system. Jail reform is what I wanted to do right out of law school and I happened to luck into getting elected. I'm more interested in doing things than trading votes."

How does he reconcile his passion for music that is by its very nature anti-authoritarian with his being so enmeshed in the system, in a position of such real and symbolic authority? Hennessey laughs, but acknowledges the complexities involved in his choice of hobbies.

"It's really a mental balancing act," says the punker.

"I have to find ways in my life to make myself more well-rounded and give myself mental health breaks. And for me mental health breaks seem to involve reading bloody murder mysteries and listening to loud and obnoxious music. It's a simple matter of finding areas in your life that distract you from being totally absorbed in your work. The Sex Pistols were certainly anti-authoritarian, but a lot of people forget that they were also very funny. Even the sheriff needs a little humor in his life."