As he zigzags mustard onto a hot dog, actor Kevin Chapman is paying no attention to the husband and wife murmuring a few feet away.
“You know him,” the guy whispers.
“I know I do,” she says. “But who is he?”
Almost famous for his everyman roles in such films as “Mystic River” and “Ladder 49” and the CBS series “Person of Interest,” Chapman gets that a lot — sometimes on the street and sometimes, like tonight, at the condiment counter at TD Garden, where he’s come to watch the Bruins.
Chapman, a season ticketholder for six years, makes as many games as he can. Problem is, “Person of Interest,” a sci-fi flavored crime thriller produced by J.J. Abrams, shoots long days in New York. Chapman, who plays NYPD Detective Lionel Fusco on the show, keeps a place in Queens — “a blue-collar neighborhood because it helps me stay in character” — but home is Hingham, where he lives with his wife, Meaghan, and their two kids.
The South Shore might seem like an odd address for a primetime actor who’s made movies with Clint Eastwood, Alejandro González Iñárritu, Lasse Hallström, and Todd Field. But at 52, Chapman, like many of the characters he plays, seems like someone for whom the trappings of Hollywood have little allure.
“Acting is what I do, not who I am,” he says, his eyes fixed on Bruins forward Patrice Bergeron carrying the puck over the blue line. “I know successful guys in LA who can’t go to the mall. How do you portray life if you’re isolated from it?”
Chapman — “Chappy” to his friends — has an improbable back story. He was a 37-year-old functionary in Mayor Tom Menino’s office of cultural affairs when, unsolicited, he got his first acting job. Denis Leary, whom he’d met a couple of times while working as a bouncer at Nick’s Comedy Stop, was in town making Ted Demme’s darkly funny drama “Monument Ave.,” and he asked Chapman if he’d ever acted.
He hadn’t, but Demme liked his look — a Dorchester native, Chapman is built like an igloo — and gave him a role. Soon after, he quit his City Hall job and moved to LA, studying acting during the day and working as a bouncer at night. Small parts on TV shows like “Ally McBeal” and “The Practice” paid the rent.
“There were peaks and valleys,” he says.
As the horn sounds at the end of the second period, most of the fans race to the taps to slake their thirst with $10 beers. Chapman doesn’t. He’s been sober for over 20 years and he plans to stay that way.
“I wouldn’t be where I am if I still drank,” he says as peewee teams push a puck around the ice.
Chapman’s texting with Buddy Yandle, a friend from Milton whose son Keith is an assistant captain on the Phoenix Coyotes, the Bruins’s opponent. (Keith was traded to the New York Rangers the next day.) The game isn’t going well for the Coyotes, and Yandle wants to meet up with Chapman.
The Bruins, moribund for most of the season, have scored four goals tonight, and Chapman is enjoying himself. He does an impersonation of Eastwood, who gave him his big break, casting him as the brother-in-law of Sean Penn’s character in “Mystic River.”
“I stank of a guy from Boston, and Clint liked that,” says Chapman. “Sometimes I’m there to make the guy on the billboard look good.”
“Mystic River” was important. It led to the Showtime series “The Brotherhood,” in which Chapman played a perfect thug; a small part in “21 Grams,” again with Penn; and a close relationship with actor Kevin Bacon, whom Chapman calls his “one real industry friend.”
Late in the third period, Aerosmith’s “Train Kept a Rollin’ ” plays over the PA, and the crowd, well lubricated on Bud Light, goes berserk. Chapman smiles. He’s friends with the band and reveals that he was singer Steve Tyler’s sober companion during the band’s 2010 tour of South America and Europe.
“Steven put it in his book so I feel like it’s OK to talk about,” says Chapman, shouting over the sound of Joe Perry’s wailing guitar. “I didn’t need to baby-sit Steven. I was just there to be, like, ‘Hey, go away’ if guys came around who wanted to get high with him.”
The game isn’t over, but Chapman has arranged to meet a few friends at Stanza dei Sigari, a cigar bar in the North End. Expensive stogies are one of his indulgences, and he’s been going to the basement bar on Hanover Street for about 10 years, sometimes watching Patriots games there with Congressman Steve Lynch.
“Steve’s been known to smoke a cigar,” he says, grinning.
Tonight, Chapman takes a seat at a corner table in the back with former Patriots (and Cowboys and Giants) linebacker Steve DeOssie, along with Mark Morris and Joey Acari, partners in The Tavern in the Square restaurant chain. Morris, who used to sing in the Boston band the Catunes, has been friends with Chapman for 30 years. DeOssie and Chapman ride motorcycles together.
“We rode across the country last spring and Steve brought 300 cigars, two pairs of underwear and some socks,” says the actor. “You’re hanging with Fidel Castro over here.”
Chapman is drinking Pellegrino while DeOssie sips Lagavulin 16, a single-malt Scotch. Leaning back in the burgundy booth, they talk about motorcycles — Harley-Davidsons, mostly — and cigars, not TV or movies. DeOssie has a Ziploc bag full of cigars and takes out a Punch Rare Corojo, a popular roll among cigar aficionados.
The room, dark and veiled in smoke, has the appealing vibe of a Parisian speakeasy. But the soundtrack is incongruous: Patrons are subjected to Taylor Swift when they ought to be hearing Nina Simone. Lighting and relighting a cigar that seems to last forever, Chapman is talking about riding his hog along a treacherous span of the Million Dollar Highway when a middle-age woman stops at the table.
“Is that Detective Fusco?” she says, leaning over to get a closer look.
“It is,” Chapman replies.
“Just checking,” the woman says. “Love your show.”