Within six years, Jorja Fox has graced three top 10 shows - ER, The West Wing, and now CSI. She’s the kind of Hollywood Success Story that seems, well, almost suspect.

They call her the lucky charm. First, Jorja Fox was gun-toting intern Dr. Maggie Doyle on ER. Then she was Secret Service Agent Gina Toscano, who protected the president’s daughter on The West Wing. When both of those story lines ended, Fox went on to play forensic-science hotshot Sara Sidle on CBS’s smash hit CSI: Crime Scene Investigation (Thursdays, 9 P.M./ET). The actress with the angelic face and raspy voice has hopscotched to yet another hit series. “She’s like out talisman,” says costar Gary Dourdan, who plays criminalist Warrick Brown, “because she’s been on all these great dramas.”

The fun for CSI viewers is following the crew as they unravel the mysteries behind assorted revolting crime scenes: lacerated bodies in shopping carts, corpses whose mouths are stuffed with apples. For Fox, 33, dealing with the nitty-gritty role can take its toll. “It isn’t even the blood and guts [that really get to me],” she says over a brunch of a chocolate croissant and cappuccino. “It’s the violence. There’s such an emptiness of soul.”

Am intriguing combination of a big-city and small-town girl, Fox was born the younger of two children (her brother is 12 years older) in New York City and raised from age 3 in Melbourne Beach, Florida. Her bother is a 78-year-old retired paper-products salesman; her mother, an Air Canada reservations agent, died of ovarian cancer at age 69 in 1996. “My mom was a child of the Depression,” Fox says. “The thing that gave her the most joy was feeding us. We were eating six meals a day.”

At 14, a crush on an older boy helped Fox tackle what had become a serious weight problem (152 pounds at age 12). At 15, the newly slim, self-described “messy tomboy” shocked everyone by willing a shopping-mall modeling contest. Fox subsequently returned to New York, where she lived in a residence for models while working and completing high school. She used her earnings over the next three years to study acting at the Lee Strasberg Theater Institute, among other schools. “My mother had wanted to be a painter and my father a writer. They didn’t do any of those things,” she says, “but they really supported me.”

It is especially poignant that in 1996 her mother was diagnosed with cancer when Fox landed her “dream role” on ER. That was the last thing Marilyn Fox ever saw Jorja do. “I was having the biggest personal crisis and the greatest professional thing happening at the same time,” she says.

The loss affected her deeply - and CSI reminds her of it often. “It’s always surprising how close [death] is,” she says. And Fox worries that her 12-14 hour days are hurting her relationships with the people who are still here. “Sometimes, I feel like I’m a terrible daughter, a terrible friend,” Fox says quietly. “If you’re lucky, people stick around.”

That kind of insecurity may explain why Fox, who’s dating a film actor (whom she won’t name), has yet to marry. “I’ve had some really great affairs, but I’m allergic to marriage,” she says.

This summer, Fox is visiting her dad in Florida before she takes a European vacation. And she hopes her lock will still hold. She calls CSI “the best job ever.” Could she do it in real life? No way, says costar William Petersen, who remembers a white-knuckled Fox clutching his arm during a helicopter ride over the Nevada desert during one episode. “She has a very delicate stomach,” he says. “She doesn’t even like looking at crime photos.”