By DAVE ITZKOFF


Strange is a relative term when applied to the work of Willem Dafoe, and yet when one looks at his fall schedule, it is also the word that jumps most immediately to mind.

In the art-house cinemas he and Charlotte Gainsbourg can currently be seen inflicting unspeakable violence on each other in the Lars von Trier suspense film “Antichrist.” Next, at the Public Theater in New York, he will don a frilly 18th-century costume and lead a giant anthropomorphic duck around the stage by its genitals in Richard Foreman’s surrealist play “Idiot Savant.” After that he can be heard in Wes Anderson’s animated version of “Fantastic Mr. Fox,” providing the voice of a knife-wielding rat.

It may be convenient to classify Mr. Dafoe’s choices as strange because they defy easy categorization. The actor himself is not in any particular hurry to explain how his choices should be interpreted. “Nobody has to know what I think about what I do,” he said in his gentlemanly growl during a recent lunch in Manhattan. “In fact it’s very important, I think, for an actor to keep their mouth shut on some level.”

No pattern emerges from the body of film work he has built over the last quarter-century. Sure, he has portrayed some unhinged creeps in films like “Wild at Heart” and “Spider-Man.” But that assessment does not account for his subdued performance in “Mississippi Burning,” his quiet heroism in “Platoon” or his comic turn in “Shadow of the Vampire.” It ignores his parallel career in avant-garde theater, where his work has been even more unpredictable.

Each project is an example of an actor following his own idiosyncratic muse; they have hardly anything in common except that Mr. Dafoe is in them. In person Mr. Dafoe, a sinewy man of 54, can be an intense, figure, owing mostly to a reptilian voice that can make the most banal utterances sound a little bit sinister. He is endowed with a metamorphic face that at first appears skeletal but can communicate a spectrum of emotion with its contortions.

“He looks very much like the Batman cartoon-he looks like the Joker,” said Mr. von Trier, who also directed Mr. Dafoe in his film “Manderlay.” “He can do strange things with his face that show he’s very much alive.”

He can also be playful and self-deprecating. Or be open and thoughtful about his work and then suddenly turn shy. Beneath all these layers is an actor who is supremely confident in the decisions he makes, yet still feels rudderless after five years away from the Wooster Group, the pioneering downtown Manhattan theater collective he helped to create. “I’ve been looking for outlets,” Mr. Dafoe said, “and I haven’t really found something that suited me.”

Paul Schrader, who has directed Mr. Dafoe in films including “Light Sleeper” and “Auto Focus,” said that he was the rare actor who did not need to find the redeeming qualities in his characters. “With Willem, you can actually say, ‘This guy is such a loser,’ ”Mr. Schrader said. “And he’ll get it and say, ‘Isn’t that great?’ He’ll play a loser like a loser.”

Those earliest psychopaths that Mr. Dafoe portrayed-a gang leader in “Streets of Fire,” a ruthless counterfeiter in “To Live and Die in L.A.”-were crucial to his cinematic breakthrough in the 1980s, even if they were the stock characters an actor gets offered, he said, “if you weren’t conventionally good looking, or you don’t have a winning, chatty personality.”

Mr. Dafoe said he liked that these roles let him tap into a darker side of himself. “On some level I’m very patient and flexible,” he said. “But on another level I’m like a little kid. If I get tired or you humiliate me or you treat me wrong, I’ll bite back.”

He added that the role of the villain “suited me emotionally” because “it’s more fun; it suits my fantasies more.”

He is still acting for directors well outside the mainstream, like Werner Herzog and Giada Colagrande, his wife of four years, with whom he frequently travels to Rome or the occasional film shoot in Buenos Aires. (“She’s got a lot of energy,” Mr. Dafoe said sighing. “So if we have a spare moment, we go.”)

For now Mr. Dafoe seemed most excited about his role in “John Carter of Mars,” a coming adaptation of the Edgar Rice Burroughs adventure novels.

Another wide grin crossed Mr. Dafoe’s face as he described his character, Tars Tarkas. “I’m a Martian warrior,” he said. “Nine feet tall. Four arms. Speak the language of the green Martian people.”

Despite some obvious physical shortcomings, Mr. Dafoe was unwavering in his certainty that he was right for the part. “They’ll make me nine feet tall,” he said, “and I’ll play those scenes.”

From art-house films to avant-garde theater to big-screen villains, Willem Dafoe’s acting roles defy categorization. / ANDREA MOHIN/THE NEW YORK TIMES