Most of Dornetto's writing experience is for television shows. She has written for South Park (2002), The Jamie Kennedy Experiment (2003-2004), Arrested Development (2005-2006), Community (2010-2011), Kroll Show (2013), Portlandia (2012-present). Dornetto has also written for short lived television shows such as Dog Bites Man (2006) and The New Normal (2013). In 2014 Dornetto appeared on an episode of Comedy Central's Drunk History, where she narrated the story of Babe Didrikson Zaharias.
Addicted to Fresno was Karey Dornetto's first feature-length screenplay and was written with the intent of being directed by wife Jamie Babbit. The films original concept developed from Dornetto's experiences of having an older sister. The film, starring Judy Greer and Natasha Lyonne, premiered at South by Southwest in 2015 and was also shown at Toronto's LGBT Film Festival, L.A.'s Outfest, Edinburgh's International Film Festival and the Frameline Film Festival.
