On television, McDonnell had her first regular part in 1980 on the soap opera As the World Turns. She starred in 1984 on the short-lived CBS medical comedy E/R. Coincidentally, she guest-starred in 2001 on the NBC medical series of the same name ER. She was nominated for an Emmy Award for her role on the show as Eleanor Carter. She played Dr. Virginia Dixon, a surgeon with Asperger syndrome for three episodes of Grey's Anatomy in 2008 and 2009.
