The Weathervane Tavern in South Hamilton is the kind of crusty neighborhood place that’s accessorized with lanterns and wreaths that may or not be left over from last Christmas. Today it’s packed with a lunchtime crowd of gray-haired ladies and North Shore families, all utterly jazzed for the one and only Billy Costa, who’s here to tape a segment for his local-cable food show, TV Diner. Costa will do a few hundred of these segments a year: In the parlance of his weekly restaurant-hopping show, they’re called "destination spots"—and they represent the backbone of his program, each one an opportunity to spend a few moments gushing over some cream sauce or spaghetti Bolognese.

Costa is greeted here as if he’s a gift from God. People jump and clap; some blush as they ask for a photo. Out from purses come the cell phones and what must be the last disposable cardboard cameras on earth. Costa never misses a cue, never resists a chance to flash a showman’s grin. "The paparazzi is here!" he says, his toothy smile filling the viewfinders. And in no time, his own cameramen are rolling while he carries on about the "ALL-YOU-CAN-EAT STEAK TIPS!"; he’s seemingly mesmerized by "A MOUNTAIN OF SCALLOPS!"; and he’s wondering to no one in particular, "WHEN’S THE LAST TIME YOU HAD A MUD PIE?!"

Most people are a little disappointed when they see TV personalities in the flesh—they’re shorter, or fatter, or have worse skin than one would imagine—but Costa looks no different in person than he does on New England Cable News or on those billboards that line the highways. Spiky silver hair stands an inch or so off his head. His skin is slightly oranged, his smile slightly plumped, his eyes slightly bugged. His animated mug tops off a 5-foot-11, 165-pound frame that is almost freakishly lean. Despite the hard sell he makes for all those lobster rolls, steak tips, and mud pies, Costa hardly touches the stuff. He subsists mostly on dainty bits of tuna or a Cheez-It or two.

For the sake of today’s show, he takes a slurp of the chowder, making sure his camera guys get it. There is no script, and only a single take. That’s how Costa does it—always. He’s all about "the flow," as he likes to say. "I’ll take live TV over taped any day; that’s where I’m most comfortable." Of course, this freestyle approach makes pretty much every segment on TV Diner look exactly the same, but no matter. As the fans who show up in South Hamilton know, there’s comfort in consistency. Also, when you’re running on Billy’s schedule, there’s not a lot of time to sweat the details.

If you live in Peoria or Seattle or even Schenectady, you probably have no idea who Billy Costa is. But if you are one of the six million people who call Greater Boston home, you have almost certainly seen, heard, or met Costa at some point. Or you soon will. Besides the TV Diner gig, he’s a self-effacing radio sidekick on the Kiss 108 morning show, and the host of his own weekly top-30 radio program. There’s also his side job as the most enthusiastic and ever-present emcee this side of Dick Clark. "I do everything," he says with characteristic, chest-bursting pride, "the malls, the retail gigs, the weddings, the fashion shows, the fundraisers."

Doing "everything" has, after more than 25 years in the game, led Billy Costa to an odd sort of celebrity, one of his own creation: hyperlocal, and singular in its ubiquity. Indeed, at a moment when it’s possible to become famous instantaneously, or to become famous for nothing, Costa stands out because he is famous in one very specific place for doing the same small things—over and over and over again. For almost three decades, no store opening or used-car blowout has been too low-rent; no charity auction or tuxedo-filled party too out of the way. Nothing is too small, it seems, for a personality this big.