In 2005, Thayer appeared in Hitch with Will Smith and Eva Mendes.
In Forgetting Sarah Marshall, Thayer plays a woman on holiday with a new husband, played by Jack McBrayer. Thayer and McBrayer reunited on an episode of 30 Rock in which she portrays Kenneth Parcell's blind, shallow love interest. She also played Grace and Leo's daughter, Lila (at age 18), in the series finale of Will & Grace (2006). In 2009, she appeared in the film State of Play as Sonia Baker, the researcher and mistress of a congressman.
Thayer stars in the Adult Swim comedy series Eagleheart, which began airing on February 3, 2011 on Cartoon Network. She appeared as Tracey Bluth in the fourth season of Arrested Development in flashback scenes. In 2012, she was featured in the music video "Sensitive Man" by Nick Lowe.
In 2014, Thayer played the sudden wife of Forrest MacNeill (Andy Daly) on the Comedy Central show "Review" for the episode "Marry, Run, Party" of the first season.
Starting in 2015, she starred in the TruTV sitcom Those Who Can't as an incompetent Teacher at a Denver high school, alongside Ben Roy, Adam Clayton-Holland and Andrew Orvedahl (The Grawlix).
