NEW YORK — In spite of herself, Chloe O'Brian has charmed the "24" audience. Her job on the Fox thriller is that of senior analyst at the Counter-Terrorist Unit, and she's a whiz, lording over her keyboard with data-slinging deftness as the nation's well-being hangs in the balance.

Each 24-episode season tracks a single day's crisis in real time, hour by hour, as agent Jack Bauer (series star Kiefer Sutherland) summons Chloe's high-tech assistance, then runs with it.

Jack (breathless from an L.A. rooftop): "Listen to me — I have a thumb drive! I need you to data-mine the files!"

Chloe (in a sure-why-not tone at her CTU console): "Upload the drive to my socket. Access code 5J55J."

But Chloe, played by Mary Lynn Rajskub, is much more than a glorified computer nerd. She's also petulant, snippy and a simmering sourpuss. An acquired taste she may be, but Chloe's very social gracelessness during three seasons of "24" has won her an unlikely viewer following.

A large measure of Chloe's appeal is due to Rajskub, whose unenviable challenge is to humanize a character defined by her scowl and techno-jargon. And she does. Convincingly.

So it's all the more bracing to find that, spared from Chloe's pressures and chronic funk, Rajskub is: pretty, funny, freewheeling to talk with; endowed with a plummy chuckle and a quirky take on life. And though single at the moment ("My psychic told me I would have problems in relationships in this lifetime," she reports with a laugh), she's upbeat: "I'm gonna keep trying."

"I don't feel like calling myself a weirdo anymore," she says, when reminded of her self-appraisal from several years ago. "How about if I say I was always a superstar? That's better, right?"

Then declaring, deadpan, that she had suffered "a life of trauma" with a name as elusive to pronounce as Rajskub (it's supposed to come out "RICE-cub"), she adds, "Early on I thought I should change it to 'Rascal' because that was easier to say."

But no more such deferential thoughts. "Rajskub" it is and "Rajskub" it will stay: "The world is stuck with it," she warns.

She has come a long way. Growing up in a Detroit suburb, the 34-year-old Rajskub confesses "I didn't like other people — or liked 'em too much. So I tried to keep a low profile, to skate by unnoticed."

But what she might like doing for her life's work remained a mystery through her teens.

She enrolled in painting at Detroit's Center for Creative Studies, then transferred to the San Francisco Art Institute. But she found she wasn't satisfied creating things you had to sell or, failing that, find somewhere to store. So she began exploring herself as a more convenient medium.

"I loved doing performance art, and I thought I was doing it seriously," she recalls. "But then someone wrote about me and said what I did was strange and funny. I thought, 'Funny?!' "

By the mid-1990s she was doing sketch comedy on HBO's "Mr. Show." She joined the cast of Garry Shandling's "Larry Sanders Show" its final two seasons, then landed a recurring role on NBC's "Veronica's Closet."

She has appeared in several films, including the current Harrison Ford hit "Firewall."

But three years ago, as "24" entered its third season and the newly created role of Chloe beckoned, Rajskub was loath to audition.

"On the page, the part was just, 'No, Jack. Yes, Jack,' " she says. "Besides, I had never watched '24.' But when I realized what it was, I realized this is a cool show."