Mary Lynn Rajskub is an actor whose characters evoke worry. It’s an ache like the one brought on when you see a person who takes her cat with her wherever she goes.

She always plays the weird girl on the verge of tears or trouble or joining a cult. She’s never sexy-weird, or secretly foxy beneath the tight bun and glasses, she is simply bizarre: the person you might not watch if it were real life. Onscreen, however, it’s hard to avert your eyes. In Punch Drunk Love she was Adam Sandler’s stentorian sister, the loudest element in a movie rife with jarring sonic fluctuations. On the hit show 24 she plays Chloe, the runt in an otherwise highly capable litter of government agents. The other characters heave an exasperated sigh whenever she walks into the room, while fans on the show’s message board call Chloe “inept.”

Yet it is portraying ineptitude and its dark underpinnings that Rajskub has mastered. She is a brilliant physical comedian, eschewing grand gestures for a series of nuanced tics, twitches, and stutters. Her communication style is Morse code rather than megaphone.

It was her skill at dismantling the audience’s ability to distinguish performance art from real life that earned her early roles on both Mr. Show and The Larry Sanders Show. Upcoming projects include the Fox series Kelsey Grammer Presents: The Sketch Show and the Gregg Araki Film Mysterious Skin.

If you can, get your hands on the bootleg “Girls Guitar Club,” a short video where Rajskub and writer Karen Kilgariff portray a pair of surly vintage-store sales girls who spend their days honing their song craft behind the counter and singing about the process. The melodies are interspersed with saccharine, hilarious personal affirmations. Rajskub and Kilgariff really can play and sing, and it’s a blurry line between earnest endeavor and comedic fodder.

This conversation took place in Los Angeles, in a coffeeshop. Mary Lynn rode her bike to the interview.

—Carrie Brownstein

I. “I’M NOT GOING TO BE LIKE, ‘WHY CAN’T I WHIP OFF MY GLASSES AND BE ATTRACTIVE?’ BECAUSE THAT’S NOT MY ROLE IN HOLLYWOOD.”

CARRIE BROWNSTEIN: In the roles I’ve seen you in, you’re often cast as the odd character. Like in Legally Blonde 2, for instance, you’re the voice of reason, more of the nerd or the quirkier one. MARY LYNN RAJSKUB: Yeah. I’m always nerdy and quirky.

CB: I feel like there’s a genre of film wherein the nerd girl is really just the sexy girl underneath, once you remove the glasses and hook her up with a hot guy. It’s her redemption yet it’s also a...