FOR the actor Will Patton, it's the end of the world. Again.

In the course of some 30 films, he has endured post-apocalyptic mail carriers, squishy parasites from outer space and the wrath of God, so this weekend's scourge -- an asteroid the size of Texas, headed straight for Earth -- should be no trouble.

Mr. Patton is appearing in ''Armageddon,'' which stars Bruce Willis and is the summer's second doomsday adventure movie. (The first, ''Deep Impact,'' was released in May.) Though audiences may be drawn most to the film's fiery special effects, Mr. Patton's supporting performance is likely to bring more attention to his idiosyncratic career, which has encompassed Off Broadway plays (''Fool for Love'' and ''A Lie of the Mind,'' both by Sam Shepard); art films (''The Rapture,'' a drama about divine judgment); obscure science fiction movies (''The Puppet Masters,'' with the squishy parasites), and surprise commercial hits (''Desperately Seeking Susan''). He may be best known as the scheming Pentagon aide in ''No Way Out,'' the 1987 political thriller starring Kevin Costner, and as the sinister police officer in ''The Client'' (1994), who tells an 11-year-old crime witness that the F.B.I. has ''a special little kid-sized electric chair'' for little boys who tell lies.

In ''Armageddon,'' released by Touchstone, a division of Disney, Mr. Patton portrays Charles (Chick) Chapple, one of 13 oil-rig workers drafted by NASA for a mission to intercept and destroy a killer asteroid. In a cast that includes some of film's most frequently employed character actors -- including Billy Bob Thornton and Steve Buscemi -- Mr. Patton, 44, plays the hero's beatifically calm best friend. Though this is his first appearance in a summer blockbuster, Mr. Patton said, he approached the role seriously, as he does all roles.

''I can't play anything until I find something that connects to my life, something I can carry as my secret map or code for the character,'' he said.

Establishing a link to his role in ''Armageddon'' wasn't difficult. As a 19-year-old aspiring actor, drifting about the country and picking up odd jobs to pay his way to New York City, he found work cleaning up an oil spill on the Mississippi River. Mr. Patton and his fellow day-laborers -- ''all drunk, or hung over, and sort of un-addressable,'' he said -- were paid to lean off the edge of a barge and, using giant mops, scoop up the oil slick.

''It was kind of anonymous,'' he said. ''As the boss was leaving in his motorboat, he says, 'Oh, by the way, if you fall in, you'll be sucked right under.' ''

Mr. Patton seemed to be on the verge of telling more stories of those days when he paused. He said he would rather keep most of the details about his life to himself. Shy of interviews, he generally avoided the publicity campaign for ''Armageddon,'' in part, he said, because he didn't feel able to discuss the film before seeing a finished print. He has instead spent the last month driving from Los Angeles back home to Manhattan. Along the way, he stopped in Idaho to do one day's work on ''Breakfast of Champions,'' an independent film directed by Alan Rudolph and starring Albert Finney.

''In a way I feel completely frightened of dealing with other human beings at all, yet here I am sticking my face in front of a movie camera all the time,'' Mr. Patton said.

Though some describe Mr. Patton as a bit reclusive, Holly Hunter, who first met him in the 1980's, when both were stage actors in New York, disagreed.

''Will is unbelievably charismatic, and he has a certain mystique,'' said Ms. Hunter, who so enjoyed Mr. Patton's performance in a 1984 production of ''Fool for Love'' that she saw the show several times.

''At first I admired him from afar,'' she said. ''I was completely taken with who he seemed to be in that play: a fantasy, of course, a complete female fantasy. Kind of an odd female fantasy, but nevertheless, mine.''

As Ms. Hunter's career soared, she twice sought Mr. Patton as a co-star: in a 1987 television movie, ''A Gathering of Old Men,'' and in the 1995 murder mystery ''Copycat,'' in which the two played San Francisco police detectives.

MR. PATTON is well known for his work in over 40 plays in New York, including experimental works with Joseph Chaikin as well as the two by Mr. Shepard, and has won three Obie awards. But he is also a favorite among film directors, both maverick and mainstream.

Nicolas Roeg, who directed Mr. Patton in the little-seen spiritual thriller ''Cold Heaven'' (1992), called him a ''marvelous, spontaneous actor.'' Mr. Roeg said reliable supporting players often run the risk of being typecast.

''But Will, because of the breadth of his talent, has not let himself be identified as a marketable piece of villainy or goodness,'' the director said. ''He's got a quality that is innate; he has a sense of threat about him. Not the threat of fear or danger, necessarily, but for the audience, the threat of something unexpected.''

Mr. Patton has volunteered for some uncomfortable jobs. He told Michael Bay, the director of ''Armageddon,'' to put him ''wherever there's fire, or explosions, or oil falling all over us, that's where I want to be, because that's what this movie is all about.''

But one of his favorite roles was in ''Cold Heaven,'' in which he played a priest. And he particularly liked working with Mr. Roeg, who, he said, was open to suggestions.

''I could pull out a picture book in the middle of a shooting day, or discuss an essay that Flannery O'Connor wrote about birds, and say, 'That's what I feel this could be about,' '' Mr. Patton said. ''There are very few people in movies who can work with that, but Nic hopes and expects that kind of exploration. If I said something like that to a lot of these guys, they'd go, 'Oh, there's weird Will again.' ''

Born in Charleston, S.C., Mr. Patton is the oldest of three children. His father was a Lutheran minister and later a chaplain at Duke University. When he was a small child, his parents ran a foster home for wayward teen-age boys on the family farm near Charleston, and every Saturday night, the boys put on plays and revues in the barn.

''I must have been about 5 years old,'' Mr. Patton recalled, laughing. ''I don't know what they were doing, but they brought me out on stage.

''And I had on this little hula skirt, and women's eye makeup, and something done to my hair. And I remember the whole house full of juvenile delinquents and me both having this moment of ecstasy. I think that's where it all went wrong.''

His interest in acting was also fueled by his father's love of movies and theater. ''He took me to see movies like 'The Heart Is a Lonely Hunter' at a nice old art theater, and I remember being really affected by that, and by Alan Arkin's performance.''

After attending public schools in North and South Carolina, and studying writing, painting and theater at the experimental Hampton Day School on Long Island, Mr. Patton spent a year at the North Carolina School for the Arts before dropping out and heading for New York.

''For the first seven years or so, I held so many different jobs while I was doing theater: selling Christmas trees, working as an elevator operator, at an all-night vegetable market,'' Mr. Patton said. ''I think I chose jobs in which I'd struggle and be unhappy, so I'd be forcing myself to get acting work.''

One of his first breaks was a yearlong stint on the daytime television drama ''Ryan's Hope,'' playing Ox Knowles, a race car driver. The producers described the character as ''a troublemaker with a heart of gold.'' Small roles in two New York-based independent films -- ''After Hours'' and ''Desperately Seeking Susan'' -- soon followed, and he seemed to be on the edge of stardom. But when Mr. Patton's next film, ''No Way Out,'' became a hit, he was far from Hollywood, starring in the New York and London productions of Mr. Shepard's ''Lie of the Mind.''

His performance in ''No Way Out'' had impressed the film's star, Mr. Costner, who soon began to write, produce and direct his own films. Mr. Costner called on Mr. Patton to play his adversary in ''The Postman,'' the post-apocalyptic fable that was one of last year's most unsuccessful films, both critically and commercially.

''People in my position are wise to cast actors like Will,'' Mr. Costner said. ''He's a powerful presence, a leading man, not just a convenient character for the so-called good guy to knock down.''

Mr. Patton has no regrets about the film.

''I don't know what was so bad about that movie compared to many others,'' he said. ''I came to think that public perception is informed by the press in a way that is not healthy.''

After ''Armageddon,'' Mr. Patton said he was searching for a new challenge, and not necessarily on the screen.

''I feel a lack in me for not doing theater for so long,'' said the actor, who has not appeared on stage since 1988. ''That's the thing that has meant the most to me in my life.''