Richard Crouse

On-screen and off Rachel McAdams defies categorization. A bundle of contradictions—she describes herself as “a daydreamer and a dawdler,” and “a very serious person” who has “always been kind of girly”—she lives in Toronto despite having a thriving career in Hollywood.

The common thread that links her movies, from the über-romance of The Notebook to the bawdy comedy of Wedding Crashers and the intrigue of State of Play is a simple, yet indefinable quality: intelligence. Her intellect informs every role she takes, even in a completely silly comedy like The Hot Chick, her first hit. It takes smarts to suggestively deliver a line like, “I hear it’s good for the skin if you take your towel off,” to a sauna full of women while playing a boy trapped in a woman’s body and still have a career once critics get through with the film.

“That brain is substantial,” says Diane Keaton of her frequent co-star, “and if you have that along with a face you can’t take your eyes off, it’s so compelling. It’s rare.”

She is a rarity, one of the few gilded members of young Hollywood who has made her work the focus of her career and avoided becoming a tabloid punching bag like her Mean Girls co-star Lindsay Lohan.

“I want to pick good projects,” she said in 2004, “I want to work with great directors and try not to put too much pressure on myself and just read things for the story and recognize when I’m drawn to something for the right reasons.”

After years of figure skating at ice carnivals, working at MacDonald’s in southwestern Ontario, studying drama at York University and appearing in forgettable TV shows (Shotgun Love Dolls anyone?) the smart and funny exposé of high school caste systems Mean Girls was the movie that put her on the map.

She modeled the flamboyantly wicked Regina George on Alec Baldwin’s performance in Glengarry Glen Ross. Spitting out lines like, “So you think you’re pretty?” through a cobra smile, she won critical praise and very nearly stole the show.

Then, just when audiences thought they had her typecast along came 2004s The Notebook, the deeply romantic Nicolas Sparks story. Given the script just one day in advance of the auditions McAdams beat out nine other actresses (including Ashley Judd, Britney Spears and Reese Witherspoon) for the now iconic role of Allie, the woman who finds freedom in the arms of a man (Ryan Gostling) her mother calls “trash.” Roger Ebert said her performance contained “beauty and clarity” and suddenly Hollywood had a new “it” girl.

Although she admits to being a “sucker for sweeping love stories” she didn’t capitalize on the breakout success of The Notebook by churning out a series of cookie-cutter romances or taking advantage of the huge offers coming her way—she turned down the role of Bond girl Vesper Lynd in Casino Royale—instead she opted for a variety of projects, none of which was a romance in the traditional sense.

She made waves as Owen Wilson’s love interest in the raunchy comedy Wedding Crashers, became an action star in Wes Craven’s thriller Red Eye and played the outspoken daughter of Diane Keaton and Craig T. Nelson in the critically lauded ensemble family drama The Family Stone.

Then, as quickly as she came to prominence, she was gone. For almost two years she was absent from screens until she took on the role of Kay, the platinum blonde focus of a love triangle between Chris Cooper and Pierce Brosnan, in the suspenseful psychological thriller Married Life. It’s the film she credits with rejuvenating her interest in filmmaking after some time off.

Since then she’s been a mainstay at festivals and multiplexes playing everything from a soldier whose boyfriend was killed saving her life in The Lucky Ones to the titular spouse in the sci fi romance The Time Traveler’s Wife and Sherlock Holmes’s beguiling Irene Adler opposite Robert Downey Jr.

Her best reviews of 2009 came with State of Play (which airs on TMN and Movie Central this month), a political drama in the spirit of All the Presidents Men. She co-stars with Russell Crowe and Helen Mirren as a Washington Post blogger working with Crowe’s investigative reporter to unravel clues in the murder of a congressman’s mistress.

With a full slate of films announced for the next couple of years—including Morning Glory with Harrison Ford and Diane Keaton and a project with legend Terrence Malick—it seems the chameleon spirit of Rachel McAdams is just as restless as ever.

“It’s fun to experiment,” she says, “I’m always kind of a slave to the character. Whatever kind of vision comes to my head I just have to go with it.”