He hates what the war made him - "a murderer," he says. He hates his bum leg, blasted by enemy shrapnel. Hates the time he lost building his future. And maybe, along with warmer feelings, he nurses contempt for his former mentor, Enoch "Nucky" Thompson, who rules Atlantic City, N.J., as the town's favors-granting, graft-collecting treasurer.
Jimmy pushes for his place back as Nucky's protege, a job he lost while he was fighting the war. Nucky tells him to slow down. But Jimmy is defiant.
"You'd be very foolish to underestimate me," Nucky warns as they face off on the boardwalk. "I could have you killed."
"Yeah," says Jimmy. "But you won't."
That is just one of many crosscurrents churning "Boardwalk Empire," HBO's wondrous new drama, which begins its 12-episode season Sunday at 9 p.m. ET.
Set at the dawn of Prohibition, when anything goes in this rollicking, stinking-rich resort town, the series boasts a robust cast including Steve Buscemi (as Nucky), Gretchen Mol, Dabney Coleman, Kelly Macdonald and, in a breakout portrayal as Jimmy, Michael Pitt.
Here is a simmering, gum-chewing fellow in a newsboy's cap, ruthless yet sympathetic as he plots how to cut in on Nucky's outlaw liquor ring.
Pitt says he threw himself into the role, down to Jimmy's limp.
"I had a brace with a stick on the back of my knee," he reports. "So, from the moment I got on set in costume to the end of the day, I couldn't walk without a limp. Every day for seven months.
"The easiest way that I know as an actor is to make it really difficult on myself," he goes on, chain-smoking Marlboros and lingering over a cappuccino one recent day at a Manhattan sidewalk cafe. "I found myself staying in character a lot. Even when I wasn't shooting, I was still working: I wasn't going out, I wasn't seeing friends. It's the only acting trick I've learned: to try to obsess."
Inevitably noted for his baby face, arresting blue eyes and pouty, pillowy lips, the 29-year-old West Orange, N.J., native seized on acting because, "I liked the attention. And it kind of evolved into a craft, a skill, which was a positive thing in my life. Then I came to New York. I never really left."
Pitt has tackled roles in more than a dozen varied, often offbeat films that include the disturbing thriller "Funny Games," "The Dreamers" (directed by Bernardo Bertolucci), a pair of movies by Gus Van Sant and "Hedwig and the Angry Inch," the 2001 musical in which he played a teenage Jesus freak who rips off a transsexual wannabe rock star.
On TV a decade ago, Pitt was a regular on "Dawson's Creek," but walked away from that hit teen melodrama after 15 episodes. It wasn't what he wanted.
"My first job where I was like, 'I made it,' I was doing a little play off-off-Broadway and getting, I don't know, $280 bucks a week," he explains. "There was nothing more satisfying than that."
"Boardwalk Empire" has been plenty satisfying, Pitt says, while claiming to have "only scratched the surface" this first season. Production wrapped in June, but the role of Jimmy and the era he inhabits "is still there. I'm still digesting it."
It is a decade ripe for storytelling, said Terence Winter, who created "Boardwalk Empire."
Clamping down on legal liquor sales guaranteed crime, and Winter is fascinated by criminals.
"People who are duplicitous and power-hungry and grabbing with both hands are always interesting," he said between scenes last June in crime boss Nucky Thompson's grand office in a luxury hotel overlooking the boardwalk.
Actually, Nucky's "office" was a set on a Brooklyn soundstage. It was not far from the lot where, in sight of the East River and Manhattan's modern skyline, a sprawling 1920s beachfront boardwalk had risen, complete with buildings and sandy beach (the Atlantic Ocean is computer-generated).
"Boardwalk Empire" occupies its era in lavish and painstakingly accurate detail, from the wardrobe and period lingo to the musical score, some of which, Winter said, was reclaimed "from sheet music that had never been recorded before and hadn't been played in 85 years."
Several of the characters are historically based, such as gangsters Arnold Rothstein, "Lucky" Luciano and a stubby young Al Capone, with whom Jimmy forms a business partnership.
There also was a real-life Nucky Thompson, who, in this densely populated series, is its centerpiece. (The character is based on real-life crime boss Nucky Johnson.)
He makes a wonderfully complex, contradictory hero. And thanks to his portrayal by Buscemi, the careworn, cadaverous Nucky is no less charismatic in his own unlikely way than a past HBO scofflaw, Tony Soprano, was in his.
The comparison is apt. Winter created "Boardwalk Empire" after years as a producer and prolific writer for "The Sopranos" (on which Buscemi appeared, by the way, as a cousin of Tony's, who ultimately whacked him). And among Winter's fellow executive producers is another "Sopranos" alum, frequent director Tim Van Patten, along with the Oscar-winning filmmaker Martin Scorsese, who directed the "Boardwalk" premiere, which Winter wrote.
Like "The Sopranos," Winter's new series has dimension, unexpected twists and flashes of dark humor, plus startling eruptions of violence.
Hear Pitt describe a scene in the pilot when he and Buscemi visit a bootleg distillery hidden in a funeral home. There, Jimmy angers Nucky by losing control with a potential business crony.
"I get into an altercation with this guy and break a glass over his head," Pitt recalls. "I talked about it beforehand with Marty, but I don't think Steve knew I was going to do it." The surprise paid off in Buscemi's reaction. "He looked like he was going to kill me. He scared me! And he never missed a beat.
"When things like that can happen," says Pitt, "anything can happen."