Cassidy also has starred in films such as "Under Fire" (1983), "The Fourth Protocol" (1987), "The Package" (1989), "Where the Heart Is" (1990), "Don't Tell Mom the Babysitter's Dead" (1991), "Vampire in Brooklyn" (1995), and "Ghosts of Mars" (2001). From 2001 to 2005, she played Margaret Chenowith on the HBO drama series "Six Feet Under" for which she received a Primetime Emmy Award nomination. From 2011 to 2013, she played Joan Hunt on the ABC series "Body of Proof", and from 2010 to 2013 starred in the HBO Canada comedy series "Call Me Fitz" for which she won two Canadian Screen Awards.