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."