In 2005, she starred in the romantic comedy Wedding Crashers, the psychological thriller Red Eye, and the comedy-drama The Family Stone.She was hailed by the media as Hollywood's new "it girl", and received a BAFTA Award nomination for Best Rising Star.
Mc Adams was 25 years old when she was cast as the mean high school queen bee Regina George, and she modelled her character on Alec Baldwin's performance in the drama Glengarry Glen Ross (1992).
In 2010, Mc Adams appeared in her first star vehicle, the comedy Morning Glory.
She then had starring roles in the films Midnight in Paris (2011), The Vow (2012), and About Time (2013).
In 2016, she played Christine Palmer in the Marvel Cinematic Universe superhero film Doctor Strange.
In 2018, she starred in the comedy Game Night and the romantic drama Disobedience.