Allison Janney enjoys stretching out creatively

• %27West Wing%27 alum stars in Showtime drama %27Masters of Sex%27 and CBS sitcom %27Mom%27
• Actress also has roles in upcoming films
• Paul Newman was big influence on her

LOS ANGELES – If her mother's acting wasn't enough of a career push for Allison Janney, having Paul Newman direct her first college play certainly made her path clearer.

Both "led to me going in that direction, although I was terrified to ever say I was an actress or pursuing it as a career, because not too many people are lucky (enough) to actually have a career," she says.

The busy Ohio native and Kenyon College graduate, who won four Emmys as C.J. Cregg on The West Wing, is enjoying an abundance of acting: Meaty roles on two first-season series, Showtime's Masters of Sex (season finale, Sunday, 10 p.m. ET/PT) and CBS' Mom (Monday, 9:30 p.m. ET/PT).

The vast difference between the roles and the shows, a period drama and a brash, multi-camera sitcom, appeals to Janney. "I like doing it all, but I love things that are messy, a little of both," she says.

The actress, who got an early career boost with a role on Guiding Light ("My father was happy, because I was able to pay my rent."), earned praise on the big screen this summer as a wild, oversharing neighbor in The Way, Way Back, adding to a resume that includes The Help, Juno, Big Night and American Beauty. She also has Tony nominations for her theater work.

But it was her role as the stalwart West Wing presidential aide that had the biggest effect on her. "Of all the characters I've played, I wish I was most like C.J. She was pretty substantial and a great role model for women. I feel that she inspired people to do better."

Janney has upcoming film roles including cameos in Jason Bateman's Bad Words and Clark Gregg's Trust Me, and a voice part in Mr. Peabody and Sherman. "They don't take up a lot of time, these parts I do in these movies, but they're always good roles because they make an impression. I like to take them and run with them."

She is happy to be busy in an often unstable field, but her ultimate goal is playing the lead in a film.

"I've been lucky so far and hope I continue to be, but I've not had that big starring role or lead role in a movie," she says. "I think there are always parts for character actors like me … but I have not yet had something that was mine. I'd love to find something like that."

Janney, who is single and "would like to find a soulmate," can bring the laughs on Mom, whether it's physical comedy or the verbal outrageousness of her character, the recovering (and sometimes relapsing) alcoholic grandmother, Bonnie. She's game for a date with Chef Rudy (French Stewart) in next Monday's "ridiculously crazy episode," says executive producer Chuck Lorre, but she can also pull off heartbreaking moments, such as discussing how she let her daughter down.

"The greatest gift is having an actress who can actually move you," he says. "She moves me."

He marvels, too, at her performance in Masters, where her straight-and-narrow Margaret Scully finds her 1950s world upended when she has an affair and later learns her husband, Barton (Beau Bridges), is gay. "When you watch her in that, it's like, 'Who is this woman?' She's a chameleon," he says.

Like other Lorre sitcoms, Mom has its share of sex talk, but Masters, by its nature, requires many of its actors to take part in scenes of intimacy and nudity.

That included Janney, 54. "I was like, 'Oh my God. Are you sure?' " she recalls saying when producers broached the topic. However, she said she was in good physical shape and thought: "I can't go back and do it earlier. So, I'll say, 'Yeah. I'll be brave. I'll do it.' "

Janney brought emotional bravery, too, in an awkward, poignant scene in which Margaret tries to volunteer for a sex study but doesn't have the required knowledge or experience.

It "is one of the most painful and beautiful sequences that any of us have ever had the experience of" seeing, says executive producer Sarah Timberman. "It's a moment of such pure vulnerability on her part, and she was completely unafraid of that. She embraced it and made something very real and very raw."

Bridges says Janney brought a similar fearlessness to the "uncharted territory" of their characters' unusual stories, details of which they learned as the season progressed.

"I felt she totally trusted me and us together," he says. "She trusts her instincts.You get in there with somebody who's uncomfortable and afraid, it's nervous time. When you sense you're in there with somebody who's confident and is comfortable with themselves as a person and an actress, the whole process becomes more relaxed."

That's a long way from someone once terrified to say she was an actress. Although much of that strength comes from her career experience, Janney thanks the late Newman for giving her a boost.

"He said he would do a favor for me, whatever I needed," she says. "I never called upon him for the favor ... but I always had it in my back pocket, so it gave me a little confidence."