Charlie’s biker is riding a tightrope in ‘Sons of Anarchy’

He plays Jax Teller, the golden-boy heir apparent to a violent, arms-dealing, drug-smuggling California biker gang.

The tattooed Jax has killed for the club and served time in prison, but the outlaws are a tight brotherhood who will do anything to protect each other, their families and their lovely small town, Charming. He’s haunted by letters from his late father — who wanted the club to go legit. But now, with a girlfriend and two young sons, the loyal Jax wants out of the club, even though it’s the only family he has ever known.

Charlie Hunnam’s portrayal of this complex character — loving father, caring boyfriend and unapologetic murderer — has helped make “Sons of Anarchy” FX’s biggest show, even topping the popularity of the network’s mega-hit, “The Shield.” Show runner Kurt Sutter explains that it’s an extremely demanding role that requires a broad range.

“You have your action stars that can do bad-ass things, then you have your more rounded, sensitive actors,” said Sutter. “And it’s a rare combination to find people who can do both convincingly, like Charlie.”

The inherent conflict between the family man and gangster roles is what makes the character so enjoyable to play, said Hunnam during a phone interview from Toronto.

“On any given day, we’ll shoot scenes that will span from a very loving scene with [his character’s romantic interest] Tara, to having fun with the boys, to having some giant heartbreaking epiphany,” said the 31-year-old, British-born actor. “And it requires a giant amount of focus and energy, but it’s good to be pushed as an actor.”

Hunnam’s upbringing helped prepare him for his conflicted character. He grew up in the hardscrabble working-class section of Newcastle, England, with a tough-guy father. Hunnam said his father’s career choices were extremely limited.

“He could have either been a coal miner, shipbuilder, factory worker or a gangster,” he said. “So he got into various things, never narcotics, but more English working-class kind” of misbehavior.

His mother was an extremely loving and bohemian woman, who left his dad to protect Hunnam and his older brother. In many ways, his childhood eerily resembles the fictional life of Jax Teller.

“Charlie understands the violence of this world in ‘Sons of Anarchy,’ because I think he grew up in it to a certain extent,” Sutter said. “Yet he’s had this incredibly warm and devoted relationship to his mom, so the parallels with Charlie’s own personal life couldn’t have been more in sync.”

Hunnam’s life of contrast doesn’t end there. With his blond hair and runway model-like features, he looks like a cross between Kurt Cobain and a young Brad Pitt. Yet he prefers roles — like the scraggly-bearded, hoodie-wearing Jax — that downplay his looks.

“I grew up fighting and being kind of a tough kid, so I felt like the way I looked didn’t reflect the way I felt,” he said.

“And so I tried to wherever possible let people know when I was pursuing roles to not dismiss me just because I’m pretty, because I pack a punch!”

There’s little doubt Hunnam is a fighter — just ask Sutter, no stranger to confrontation either. This summer at the Television Critics Assn.’s press tour, the actor and the show’s creator had a very public spat that resulted in Hunnam’s being conspicuously absent from a panel. Sutter has since taken the blame for the disagreement.

“During the course of a season, when I’m buried in writing scripts and in post and working 80 or 90 hours a week, I isolate and kind of shut everybody out,” Sutter explained. “And it’s been such a big emotional season for Charlie, he really needed more feedback from me, and he didn’t have access to me.”

Added Hunnam: “We’re kind of highly strung, volatile guys. And I had approached him about something, and I felt he dismissed me, and I got really, really angry and kind of exploded at him…. But by the next day, we talked it through and hugged it out, and told each other how much we respected and loved each other, and moved on.”

Hunnam got his start in acting during a drunk, last-minute, Christmas Eve shopping spree, when a talent scout for the British children’s show “Byker Grove” approached him. He then appeared in the British version of “Queer as Folk,” his character becoming a national gay role model amid England’s raging political debates about homosexual age-of-consent laws.

In the late 1990s, “when that show came out, the legal age of consent for heterosexuals in England was 16, but for homosexuals it was 18,” Hunnam said. “My character was 16, so I was able to have heterosexual but not homosexual sex, so it just threw, like, a can of gasoline on that debate.”

He moved to Hollywood, landing a role in the Judd Apatow TV series, “Undeclared,” and also in such films as “Nicholas Nickleby,” “Cold Mountain” and “Green Street Hooligans.” Finally, he was cast in “Sons,” which is enjoying its strongest ratings ever, averaging about 5.5 million viewers per episode.

The burning question for “Sons” fans is, will Jax be able to get out of the club?

“I don’t know if Jax working for the post office is really that compelling television,” laughed Hunnam. “And I don’t want to see the end of the show because I’d be heartbroken to leave it.”