His grandfather was a union organizer on the Boston waterfront, and his father-in-law recently retired as president of Local 1421, one of the last demolition locals in the country.
Still, Ken Casey sounded absolutely sincere when he said he doesn't feel obligated to sing punk anthems about working-class grunts and their labor unions.
He does it, he insists, because he knows firsthand why unions are important and because he's tired of the hypocrisy he has seen over the last several years regarding America and its blue-collar work force.
"Everyone loves to make heroes out of people doing tough jobs," he said from the road recently, "but no one wants to pay them what it's worth or make work conditions better for them."
The heroes and the tough jobs he's talking about have made good stories recently: coal-miners pulled from a mine in Pennsylvania; scores of firefighters, police officers, ironworkers and other hard-hat laborers who responded to Sept. 11; American troops sent to Iraq and Afghanistan, many of whom come from working-class backgrounds.
So Casey and his Celtic punk band, the Dropkick Murphys, take a message to their crowds.
"Unions are a fading thing in this country," he said, "and we want the younger generation to recognize the importance of unions and what they meant to America: They built it."
That audience, he said, is a mix of people who are there for different reasons -- and not always to be preached to. But that doesn't matter: "You don't have to have a friggin' union job to come and see us," he said.
"Some of them are just younger kids, punk fans who don't give a (bleep) about what we say, which is fine. A few are older guys who are fans of Irish music who have adapted their tastes to the way we do Irish music.
"But we get a lot of fathers with sons, and I've noticed that they seem to be listening. They seem to get our message, which makes it even more gratifying."
That message has reached some people in high places. The highlight of his music career, Casey said, was playing an acoustic set for AFL-CIO President John Sweeney a couple of years ago.
More recently the band heard from Nora Guthrie, Woody Guthrie's daughter, who invited the Murphys to peruse her father's archives for lyrics they could turn into songs, the way Wilco and Billy Bragg did on the "Mermaid Avenue" albums.
"Woody Guthrie was a guy who shared many of our political beliefs," Casey said. "We have an enormous amount of respect for him. Most of the stuff we chose either involved labor topics or mentioned Boston, our hometown."
The Murphys have put three sets of Guthrie lyrics to song, including "Gonna Be a Blackout Tonight," which made it onto the band's latest record, "Blackout." They chose those lyrics back in the winter of 2002, Casey said, yet given recent world events, the song has accidentally taken on a deeper meaning.
"First of all, we picked it because we already had some music written that we knew would fit the lyrics as soon as we read them," he said. "The song is about World War II air raids in London. But because the record came out a couple of months after the bombing of Iraq, a lot of people thought we were commenting on that.
"And then during the big blackout last month, we got e-mails asking us whether it was a publicity stunt. The real funny thing is, Nora called us and told us she was in the archives looking through lyrics when the lights went out."
Not all the "Blackout" tunes are loaded with political ammo. "The Dirty Glass" is a ribald kiss-off that recalls "Fairytale of New York," the Shane MacGowan/Kirsty MacColl duet on the Pogues' "If I Should Fall From Grace With God." And "Time to Go" is a rousing paean to hockey and Boston's beloved Bruins.
But the thematic thrust of "Blackout" is respect and redemption for people who work hard, live right, and still get left behind by an economic system that has streamlined and downsized too many people out of a living.
Take "Worker's Song," the second track, which starts out: "This one's for the workers who toil night and day/By hand and by brain to earn your pay/For centuries long past, for no more than your bread/Have bled for your countries and counted your dead..."
"Not too many people in the music business are a voice for these people," Casey said. "By no means are we trying to represent the entire working class. But we have a voice, so we put songs on a record and give a couple of hundred thousand people the chance to hear our message."
What they hear beyond the message is the sound of a band that has discovered the difference between a job and a calling.