Her interest in acting began early, with her performing in Shakespearean productions in summer theater camp at the age of 13. She pushed forward and graduated with a BFA degree in Theater from York University.
She kicked off her career with an appearance on the 2010 MTV pilot, Shotgun Love Dolls, during spring break from York University. This was followed shortly after with an appearance on an episode of the Disney show, The Famous Jett Jackson, in 2001.
Her Hollywood debut came in 2002 with a role in the film, The Hot Chick (2002), which got her some attention from critics. From there she went back to Canada to star in the TV series, Slings and Arrows, a comedy about backstage theater life. For her work with this show, she received two Gemini Award nominations, one of which she won.
McAdams' claim to fame came in 2004, with her role as Regina George, the obnoxious and fiery queen of the jungle from Mean Girls (2004). The film did well in the box office, with critics, and won her two MTV Movie Awards. She followed that up with a performance in The Notebook, where she played a wealthy Southern belle. "I'm a sucker for those sweeping love stories. When I read the script (The Notebook), I couldn't stop crying! I just had such a powerful, instantaneous reaction " it was written so well." This film was also a box office success, and went on to become the predominant romantic drama for the young generation. McAdams' performance didn't slip past critics either, who gave her much praise for the role.
During shooting, McAdams and co-star Ryan Gosling had a difficult relationship on set, and felt that they hindered each other's work more than they helped. But somehow, after shooting was complete, McAdams and Gosling began dating. By mid-2007, the couple decided to call it quits; "I guess each relationship is different. That's what I love about relationships. Even when they end, you've learned so very much, so much to take into your next relationship and to take into your life. It's the greatest thing that comes out of an ending " so it depends on the person."
In 2005, McAdams starred in three films, each pushing her acting abilities in a different direction and making her a force to be reckoned with. She starred in Wedding Crashers (2005), playing the part of Claire Cleary who is caught in a love triangle along with Owen Wilson and Bradley Cooper's characters. Critics praised her for her ability to add depth to a female character, since women in these types of movies tend to be more eye candy than anything. From there, she branched off in a different direction, starring in the Wes Craven thriller, Red Eye (2005). She received more admiration from critics for being able to push the boundaries of her abilities and play something different, while also being very convincing and full of depth. Her last film of 2005 was The Family Stone (2005), a family drama that saw her take on the role of a disheveled and disdainful sister, which was also different from her normal roles. This film, like her others from this year, did well in the box office and earned her lots of positive attention from critics. "I want to try a lot of things that I haven't tried. You know, I did a thriller (Red Eye) after this, because it was so different and it was a genre I hadn't worked in yet. Then I did a beautiful family ensemble drama. And next? I don't know. I might go off to do a small independent in New York. I'm not sure. The quality of materials is important but, basically, I'm open to anything. I like to stay open to anything."
McAdams was becoming a big name in the industry at this point and was asked by Vanity Fair to come do a photo shoot along with Scarlett Johannson and Keira Knightley for the March 2006 cover. When she arrived, she came to realize it was going to be a nude session, and then left. Shortly after, she left her publicist because he failed to mention that in advance. "Nudity for fictional characters is as normal and mundane as eating breakfast. What bothers me is our culture's obsession with nudity. It shouldn't be a big deal, but it is. I think this overemphasis with nudity makes actors nervous. There's the worry about seeing one's body dissected, misrepresented, played and replayed on YouTube."
After this incident she decided to lay low for a while. During her time-off she turned down parts in The Devil Wears Prada (2006), Casino Royale (2006), Mission: Impossible III (2006), and Get Smart (2008). She returned to the screen in 2008 with the independent film Married Life.
2009 was the year that saw McAdams get back on the fast track with three more big performances in State of Play, The Time Traveler's Wife, and Sherlock Holmes. Each of these films went on to do well in the box offices and earned her praise from critics. 2010 saw her take the lead in the comedy, Morning Glory, in which she once again did well, despite the fact that she wanted to turn down the role because she felt she wasn't funny.
Her big role in 2011 was in Woody Allen's Midnight in Paris, which was another chance for her to play something other than "beautiful girls." The film did very well in the box office and was nominated for a few different awards. Her second 2011 appearance was a cameo in the sequel, Sherlock Holmes: A Game of Shadows.
In 2012, McAdams came back to romantic dramas with the film The Vow. She also starred in Terrence Malick's To Wonder along with Ben Affleck, as well as Brian DePalma's thriller, Passion, alongside Noopi Rapace.
During shooting for Midnight in Paris, she met actor Michael Sheen, with whom she currently has a relationship.