Hollywood was never part of Paul Greengrass’ plan.

For more than two decades, he had been perfectly content operating within the world of independent British television, directing challenging work about difficult subjects — racism, corruption, terrorism and war. Then “Bloody Sunday” won the Golden Bear at Berlin in 2002, and the American studios came calling.

And Greengrass was listening.

“I was looking to do something new,” says Greengrass, whose subsequent work with Universal earned him both an Oscar nomination for directing and Variety’s 2007 U.K. Film Achievement Award.

Not every studio would have humored Greengrass’ particular career path — or given him the keys to such upcoming projects as “Imperial Life in the Emerald City” and “They Marched Into Sunlight,” thinking persons’ pics about the Iraq and Vietnam wars, respectively. But Greengrass brought a singular energy to U’s budding Bourne franchise, and in return, the studio stood behind edgy personal projects like “United 93.”

“I came to Hollywood to have an adventure, and the adventure was to make a commercial film,” he says. “I’ve never been interested in creating marginal work. I was always very proud that in my earlier days I was able to make films about Ireland or a race murder that would be seen by big audiences. If you have something to say, it’s a good thing if you reach an audience.”

In that respect, Greengrass’ decision to go Hollywood was all about trading up, not selling out.

He wouldn’t make just any movie, selecting “The Bourne Supremacy” as a challenge suited to his particular strengths. “The Bourne franchise was a tremendous collision between a mainstream Hollywood commercial thriller and a kind of quirky, indie, stylistically bold sensibility — that was (executive producer) Doug Liman’s genius,” he says.

Style boosted substance

Though it would take several American movies for critics to comprehend fully what he was up to, Greengrass applied the same guerrilla verite technique he’d been developing in the U.K. to what might have otherwise been a straightforward genre picture.

The result was a revolutionary sort of action movie, full of fast cuts and immersive camerawork. For a work of sheer fantasy, the experience felt like watching something torn from tomorrow’s headlines.

“That was very satisfying for me, actually. We’ve shown that you can do good work in the mainstream,” Greengrass confides. “Those franchise films are basically the gigantic engines that power the industry. Having done a couple, I’ve got a very healthy respect for them, because I know how damnably difficult they are.”

But it hasn’t all been smooth sailing since Greengrass arrived in Hollywood. He wasted five months trying to get “Watchmen” off the ground at Warners, only to see it stall. But “The Bourne Supremacy” paired the director with a new team of collaborators — most notably, camera operator Klemens Becker, editor Christopher Rouse and assistant director Christopher Carreras — making it easy to rebound onto his next studio project.

“I felt a bit like a musician when he decides to leave a band and work with different musicians,” Greengrass says of coming to America. “It’s good for you because it makes you learn.”

And yet, for all the benefits increased Hollywood resources could offer, Greengrass found that his style worked best under limits. “I remember (producer) Frank Marshall saying to me very early on, ‘My job on this film is to put you in a box every day, and your job is to find your way out,’ and that’s true. You need a box to work.”

Confined and dandy

“United 93” was a perfect example of creative solutions emerging because the action was confined to either the plane’s cabin or air traffic control centers. Applying that same lesson to “The Bourne Ultimatum,” Greengrass set complex action sequences in places where a huge unit simply couldn’t operate: Waterloo Station, the streets of Manhattan and the Medina of Tangiers.

“That’s the way we kept the indie spirit alive in this big-budget film,” Greengrass says. “It’s something I’ve thought about a lot this summer going into this Iraq film.”

Like “United 93,” he expects “Emerald City” to be challenging because debate still rages about how the U.S. is handling the Green Zone.

“It’ll be decades before the judgment of history is in,” he says. “You have to feel some responsibility to that, and I think it’s one of those things that Hollywood in its history has been very good at. You can think of many examples, the most obvious being the Vietnam movies.”

Greengrass sees another project he is developing for Universal, “They Marched Into Sunlight,” as an opportunity to expand that conversation. It was Tom Hanks who sent him David Maraniss’ book, which divides its time between a tragedy on the front and the resistance movement on campuses back home.

“One of the most exciting things about ‘Sunlight’ is that it weaves the two in together,” Greengrass says.

The common thread through all his work has been finding ways to make contemporary issues accessible to mainstream audiences. “That’s another example of (Universal) supporting me to operate across the waterfront,” he says. “They understand that you need to develop, that you need to do different things.”