On a thriller ride

COMEDY fans know Mary Lynn Rajskub for her satiric work on the HBO comedy series “Mr. Show With Bob and David” and “The Larry Sanders Show” and in such features as “Legally Blonde 2: Red, White & Blonde,” “Road Trip” and as Adam Sandler’s sister in Paul Thomas Anderson’s “Punch-Drunk Love.”

But two years ago, the 34-year-old Michigan native made a sharp turn in her career by joining the cast of Fox’s thriller series “24” as the annoyingly brilliant computer geek Chloe O’Brian, who helps Jack Bauer (Kiefer Sutherland) find the bad guys as a member of the Counter Terrorist Unit in Los Angeles. Last season, Chloe got the opportunity to leave the confines of the CTU headquarters and work in the field -- even shooting to kill terrorists.

“It was a blast,” she enthuses. “I was kind of against guns at the beginning of the day, but once I practiced shooting it, it was like -- ‘This is cool.’ ”

The actress, who began her career as a performance artist, also appears in the new Harrison Ford thriller, “Firewall,” which opened Friday. Rajskub plays Janet Stone, the loyal assistant of a bank’s computer security specialist (Ford) who helps him save his family from vicious bank robbers.

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You are a computer genius on “24” and an assistant extraordinaire in “Firewall.” How are you with computers in real life? And have you ever worked as an assistant?

I am really bad with computers. I can’t take pleasure in watching TV anymore because I can’t figure out how to turn it on.

I never worked in an office. I always waited tables. I was twentysomething looking for a job and tried to be a bagger at a grocery store once, but I think the boss sort of sensed I was, like, trouble. He didn’t even let me apply.

I also worked at the Hard Rock Cafe at the Beverly Center [as a waitress] and at the theaters there. That was another one! I wasn’t concession-stand material, so I had to take tickets.

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Did you ever do anything dramatic before “24”?

I mostly auditioned for comedies. I’m good at it, and I love it. I didn’t even audition for that many dramas. I actually didn’t want to go on the audition for “24.” I had had a really bad “CSI” audition the week before.

There was a different tempo in the [audition] room. They were really serious. People weren’t saying, “Hi, how’s it going?” I don’t think they understood my approach. I don’t remember what the part was, but there wasn’t enough to really grab on to.

With “24,” I called my agent after I got the material for it. The character really wasn’t written yet, so on the page it was, like, “Yes, Jack, I will.” So I said to my agent, “I don’t think I can really do anything with this.” When I called my mom, she said, “That show is amazing.” Once I saw the show, I said, “It’s a really cool show. I am going to be a fool if I don’t go.”

The producer met me in the hallway [when I went in to read] and he said, “I saw you in ‘Punch-Drunk Love,’ and I know there is nothing on the page, but we are going to write a part for you.”

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How far in advance do you know the plot machinations of “24”?

You get the script like a week ahead of time. But once you are in the middle of the season, you kind of know that certain things have to happen.

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“Firewall” is your biggest film role to date, and most of your scenes are opposite Harrison Ford. What was he like to work with?

He puts people at ease, and he’s funny. A lot of times when you meet celebrities that big, they can have that aura that you can’t really [approach them], but he goes out of his way to be friendly.

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Were you always interested in acting?

Yeah. I did children’s theater when I was young. I think one of my first roles was being an Oompa Loompa in “Charlie and the Chocolate Factory.” I was about 6.

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But you studied painting.

I went to school for painting in Detroit, and I finished school in San Francisco. I started doing performance art -- a little bit in Detroit and then in San Francisco. I met a bunch of comedians and started doing comedy shows in San Francisco.

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What types of performance art did you do?

Well, some people did stuff that was more sculptural, like dressing in a body sock and falling down two flights of stairs. Mine was more like audience-related. I was always sort of delivering a monologue that didn’t make sense, and I had a cardboard podium and I was trying to get something across that was confusing. I tied my foot up to a ceiling with a string and had a bowl of jellybeans on a stool outside of my reach and did a monologue.

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Well, I can see where that would lead you to comedy.

I started doing live shows with a couple of friends [in Los Angeles] -- David Cross and Bob Odenkirk. I participated in a lot of their live shows that led up to them doing “Mr. Show” on HBO. That was a fun time because I was doing something I really love. I was around these people who were talented and trying to do something unique.

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With your “24” work schedule, do you get any time to perform live?

I actually did a live performance a couple of months ago. It was hard because I was working. But I scheduled four half-hours for myself every two weeks at 9:30 p.m at the Tamarind Theater, which is now [the site of] the Upright Citizens Brigade Theatre. It’s new material, and I’m really glad I did it because the only way to generate stuff is to do it on stage.

-- SUSAN KING