Mark Wahlberg is pointing a gun at a powerful yet corrupt politi-co who bears an uncanny resemblance to Dick Cheney. Wahlberg cocks the weapon. The Cheney-like politician looks shocked. “You can’t kill me!” he says, outraged. “I am a United States senator!” Wahlberg sneers, “Exactly!” And then, bang! Bye-bye, Dick Cheney.

It’s just one of many moments in Wahlberg’s new movie Shooter that’s designed to make you simultaneously thump the air and raise an eyebrow. For the movie, about an innocent army sniper on the run, is a Rambo -esque paean to ballistic mayhem that’s nonetheless filled with enough Bush-bashing subtext to make it positively seditious in tone. References to Abu Ghraib, WMDs and government oil lust abound.

Today, however, at 35 years old, casually cool in T-shirt and jeans, slumped in the corner couch of a Knightsbridge hotel and still basking in the career glow of his Oscar-nominated turn in The Departed , Wahlberg is far more politically agile than his movie. “I love the fact that it has something to say,” observes the actor, whose career has advanced rapidly and vertically from the likes of Boogie Nights to The Perfect Storm , Planet of the Apes and beyond. He continues, cautiously: “When you see the poster it looks like an action movie, but then you find out that it’s a character-driven piece with, er, something to say.”

Yes, but isn’t that something actually quite revolutionary in spirit, quite subversive? You know, “Bring down the Government!”? “At the end of the day it’s all about entertainment,” he says, wincing slightly at his own political correctness. There’s an uncomfortable pause, and then he finally snaps. “But it’s a good time for it, too. There’s an election coming up and, well, we’re all ready for change.”

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Shooter from the hip

Mark Wahlberg uses his delinquent past as jailbird and rapper to add menace to his movie roles

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Wahlberg, you sense, is on his best behaviour. And has been for some time now. The actor, the youngest of nine children, who grew up in the tough Dorchester district of Boston and once served 45 days in Deer Island House of Correction for violent assault, is an ambassador for the transformative powers of the profession. Ask him, for instance, if the rumours about his frequent and heady clashes with Martin Scorsese on the set of The Departed are true, and he replies obliquely: “No. Marty did whatever Marty did to get me into the particular head-space he needed me to be in. There were no creative differences. It was a love-fest.”

He says this with a smirk that’s self-aware to the point of parody. And yet he adds, frankly, that he’s been on difficult sets before. “ Boogie Nights was like that,” he says, referring to his breakout movie, one that co-starred an allegedly tricky Burt Reynolds. “Some talented people on that set felt like they weren’t getting the breaks they deserved and were going to use the movie as an opportunity to really show their stuff.”

Another difficult set was David O. Russell’s I Heart Huckabees . Leaked backstage footage from that 2004 comedy, featuring Lily Tomlin and Russell violently butting heads amid an orgy of expletives, has recently been playing on the internet.

“Yeah, but that movie was a whole other experience,” Wahlberg says. “David is a unique guy, and making movies can be difficult. And Lily was just upset. The cameras are rolling, you’re doing the scene the way it was written, and he’ll just say: ‘That sucks, try this!’ Which can be tough.” The most intriguing aspect of the footage, however, is Wahlberg himself. He simply sits patiently, with a Zen-like calm, behind Tomlin and the co-star Dustin Hoffman, while all hell breaks loose. “Lily told everybody to f*** off except me,” he says, proudly. “And Dustin, being the ball-buster that he is, said, ‘How come you didn’t say f*** you to Mark, huh? Are you scared that he’s going to kick your ass?’ ”

And surely this is the truth about Wahlberg? That he carries the weight of his own battle-scarred history into every role. That implicit in every performance, even the softest ones, is the possibility of violence, or at least the unleashing of controlled aggression (what else are those enormous biceps for?). Certainly his directors see it. Both Russell and Antoine Fuqua, director of Shooter , have said that Wahlberg’s defining trait is his unique combination of street toughness and vulnerability. “Well, yeah, I’m a sensitive and caring person,” Wahlberg says. “But I also grew up pretty hard and tough, and I think that people sense a lot of real-life experience in me. It’s something that can’t be played with technical tricks.”

Wahlberg’s real-life experiences have included teenage years of petty crime, police arrests and drug-taking, followed by a brief bar-brawling crotch-grabbing era of super-stardom as the pumped-up whiteboy rapper Marky Mark (highlights include a fight with Madonna’s entourage at an LA party, plus dedicating his ghost-written autobiography, Marky Mark , “to my d***”).

Then acting came along, he says, and everything changed. From the moment he stepped in front of the camera, as soft-spoken Private Tommy Haywood in Penny Marshall’s Renaissance Man , he knew he had found his niche in life.

Along the way he rediscovered the lost Catholicism of his youth, and found emotional security and stability with a partner, a former model, Rhea Durham, with whom he has two children, Ella and Michael. He says that more than anything, more than acting even, fatherhood has transformed him. It’s made him even more responsible, more disciplined. “I can’t be as reckless as I used to be,” he says. “I want to see my kids grow up. I want to point them in the right direction.”

And yet, is there not a sense, somewhere deep inside, that the old Mark, the Marky Mark, is just dying to get out? Can anyone really be that reformed? Wahlberg checks himself before replying. He fidgets. You just know he’s thinking, “Right answer or real answer?” Finally, he says, slowly and directly: “Every day it’s a struggle to wake up on the right side of the bed. To have a positive attitude and to do the right thing. It’s so easy to slip back into the negative way of looking at things.”

In the meantime, he has a slew of high-profile movie projects looming, including M. Night Shyamalan’s latest spooker The Happening , as well as a sequel to The Departed . “I’m hoping to make it,” he says. “We want it to be as good as, if not better than, the first, which is not an easy thing to do. But Marty’s involved, so anything can happen.”

But as for long-term ambitions, he’s not exactly counting on any lifetime-achievement gongs in the future. “I’ve gotten a lot more out of this business than I expected,” he says, half-shrugging with Marky Mark street smarts. “I don’t expect it to last for ever. I look forward to getting old, fat and forgotten about.” And for once you kind of believe him.

Watch the Shooter trailer

Shooter is released on April 13

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