“My family were Kellys,” he says, on the phone from Atlanta, “so it was a big day for us. You’d go to Catholic school and wear green sweaters. Go to church. Your grandmother would make you corned beef and cabbage and all that. Then, later on, it was kind of like you get together [with friends] and be an idiot - the parade in Southie, all that drunken revelry. Like Mardi Gras Part Two. But for me, the last 16 years, St. Patrick’s Day has meant you’re playing a show.”
     Dropkick Murphys tour all over the world, but the Boston-based Celtic punk band has long laid claim to the St. Patrick’s Day celebration in their hometown.  They’ve played as many as seven consecutive soldout shows keyed to the holiday. They began doing this in 1997 at the Lansdowne Street club Avalon, and then continued in the same spot when the old club was knocked down and it became House of Blues. This year, Dropkick Murphys repeat two things from last year: They will play House of Blues on Sunday March 17, and an even-more intimate show at the Brighton Music Hall the previous night, a benefit for their Claddagh Fund. The big new wrinkle is they're kicking it off with a show at the TD Garden, Friday March 15, an event called Dropkick Murphys Irish Festival with Black 47, The Mahones and Old Man Markley. Acoustic music on the concourse state with sets by Old Brigade, Brian McPherson and Sun Cooked.

     “We try to keep people on our toes about what we do and make it a big deal,” says Kelly. “So we thought about the idea of doing the Garden. We’d tried a couple of other times, but there were problems with permits and logistics. But having done Fenway Park gigs, we learned about logistics and just the experience of playing bigger festivals over in Europe, knowing what to expect in terms of problems and solutions. We announced it onstage when we played the Bank of American Pavilion on the waterfront [last year] so luckily it fell into place.”

    A lot has fallen into place for the hard-working group, which put a distinctly American – and particularly Bostonian – twist on the Celtic punk sound the Pogues pioneered in the mid-1980s. Dropkick Murphys, which boasts as many former members as it has current members, has always been led by singer-songwriter-bassist Ken Casey, the founding member and sole original. Casey often writes about, or creates characters from, his old stomping grounds. The music brings a gritty slice of Boston life to the world at large, doing for rock ‘n’ roll what Dennis Lehane has done for crime fiction. Their best-known songs include the Red Sox and Bruins-friendly rockers, “Tessie” and “I’m Shipping Up to Boston.”

    I’ve talked to Casey a bunch over the years. He’s told me this about his band and his writing: “The songs are very story-specific, not broad-based. I know you take creative license, but they seem rooted in reality. It’s really people we know. We come across stories. Sometimes the names and places are changed to protect the guilty, but on the other hand, I always found – and this comes from the Irish music end of things - why tell it vaguely? The storyteller approach seems to fit. Look at Boston. The history has such a cast of characters. Why wouldn’t you document someone’s life and give them the history they deserve? That’s the cool part about being able to make music. Somewhere, some day, somebody’s going to be going through an attic long after we’re all gone, and maybe find a bad EP called ‘Boys on the Dock,’ recorded poorly. They’ll look back and laugh at that, as we did when we heard the original version of “Tessie” from 1903. Then, they might pick up the lyrics and read about my grandfather.

   I told him I loved the mixture of anger, rage and celebration.
     “There’s nothing better,” he said, “than going on stage and getting to vent that pent-up feeling of whether it’s rage or anger or frustration. But there’s also nothing better than putting a smile on people’s faces and making them want to jump up and down and want to party. I’d say once again it goes back to influence of Irish music: What other style of music can you sing the most depressing, potentially angry song about death and people are arm-in-arm like you’re singing ‘Happy Birthday’ or something? I’m a born pessimist who’s worked very hard to become an optimist. I come from a long line of pessimists. Maybe I have a house and a car now, but you can never change what you were born into. I certainly don’t run in a circle of socialites. And I still want to document life for the people I know.

    Dropkick Murphys music works elsewhere, suggests Kelly, because “everybody has a home town. Local patriotism isn’t as prevalent as it used to be, but we have a lot of that.”

     In making parochial songs universal, Kelly cites a 1904 novel by C.K. Chesterton, “Napoleon of Notting Hill.” The protagonist “came from this little neighborhood which ended up seceding from London because they’re so proud of their neighborhood. We’re not going to secede from the USA or anything, but I think people anywhere can relate to it: It’s OK to be proud of where you come from and there’s a lot to be proud of in Boston. “

    The band comes from working-class and pro-union roots. Casey writes from that viewpoint and has a left-of-center perspective similar to Bruce Springsteen, a pal who joined them at House of Blues for a few songs in 2011.

    Casey and co-lead singer Al Barr make their points with growling vocals and high energy punk rock, spiked with Celtic sounds from bagpiper and tin whistle player Scruffy Wallace and mandolinist/accordionist Jeff DeRosa. “But we’re not up there soapboxing,” Kelly says. “Leave your politics at the door, have a good time and after the show walk away with a smile on your face.”

    There’s aggression and anger in the songs. Always has been, always will be. “Everything can’t be la di da,” says Kelly. “I don’t want to sound like a cliché, but a lot of times what we sing about are reflections on what’s happening in the world. There are lighter moments in our music and I think there are a lot of dynamics. But we like punk rock. That’s just the way it is.”

    Their 2011 album, “Going Out In Style,” was an ambitious, semi-conceptual effort, based around the up-and-down world of a character named Cornelius Larkin. Their latest album, “Signed and Sealed in Blood,”  is more back-to-basics, and starts with a ferocious rhythmic hammering and the line, “The boys are back, the boys are back and they’re looking for trouble!”

    “The tunes are not over-analyzed or heavy as far as subject matter,” says Kelly, “with a couple of exceptions. It was almost like the old days, because with the early stuff, you have your whole life to write your first album and a year to write your second album. For this, several songs came together in a matter of hours. We’d been playing them on the road in Europe for months before we recorded almost any of them, so we had that kind of luxury of developing  songs like a young band does, playing them together before you record them and just putting them down – Boom!”

   Alcohol factors into more than a few Dropkicks’ songs. And if there are misconceptions about the band, Kelly says, the chief one is “this preconceived notion that we’re Shane MacGowan times seven.” (He’s referring to the brilliant but oft-soused singer-songwriter for the Pogues.) Some members of the Dropkicks, including Casey, do not drink at all anymore.

   “What we do,” Kelly says, “is stay healthy and put on a good show. We can’t call in sick. And we don’t want to screw over the people at the next show. If you’re not giving 100 percent, go the frig home. That’s one of our mantras. You save the party for afterward. “

   The other, not unrelated, idea is that the drinking songs are all just raucous good-time songs.

   “A lot of people think we’re just celebrating being a drunken maniac,” Kelly says, “but if you really read the lyrics it’s definitely looking at the dark side of things. Like in traditional Irish folk tunes, where there’s a happy-sounding song that sounds like a celebration of debauchery, but could be about a funeral or a famine. It’s that dichotomy that’s an aspect of our sound.”

    At the Boston shows, you can expect to see a troupe of young female Irish step dancers and backing strings and vocals from the Cape-based Parkington Sisters.

    “Ever since our first album we’ve had strings and other instrumentation on there that we didn’t necessarily have the capability to reproduce live,” Kelly says. “What’s good about the Parkingtons is they sing like angels, first of all, and the last couple of albums they’ve been involved in the studio too, lending their smoothness to our rough voices and some really nice string parts. It gives people more breadth as far as the sound and songs go.”

   And in concert, he adds, the Parkingtons give fans “something nice to look at rather than a bunch of mamalukes.”

    What’s a mamaluke? Kelly laughs. You have to go into the Italian subculture for that one. He says he learned it from a friend in the hardcore punk band Agnostic Front.  A mamaluke is a man – it’s always a man - who’s deemed both destructive and silly.

(This is an expanded version of a story that ran in the Cape Cod Times Friday March 8.)

Friday March 15 at TD Garden, Causeway St., 7 p.m. Tix: $40-$35; Saturday March 16 at Brighton Music Hall with Colin of Arabia and Penalty Kill (Tix and times: TBA.); Sunday March 17 House of Blues, 15 Lansdowne St., 7 p.m. Jim Locky & the Solemn Sun and Rebuilder (Tix: $65-$32.50.) www.dropkickmurphys.com