She has starred in some TV movies, and her best-known role is reporter Kristine Walsh in the 1983 miniseries V and its 1984 sequel V: The Final Battle.
Other film appearances include Plaza Suite (1971), The Other (1972), The Candidate (1972), Getting Straight (1970), Breakfast in Bed (1977) and Shadow of Doubt (1998).
[3] She has made guest appearances on TV shows, including Little House on the Prairie, Dragnet, Adam-12, The F.B.I., Highway to Heaven, Love, American Style, Dan August, Sanford and Son, Ironside, Falcon Crest, L.A. Law, All in the Family, Cannon, Hawaii Five-O, The Waltons, and The Fall Guy.
Sullivan wrote the play J for J (Journals for John) which was prompted after she found a packet of unsent letters (in 1995) written by her father decades earlier to her mentally disabled older brother Johnny (thus, journals for Johnny).
She is the former sister-in-law of songwriter Jimmy Webb, who was married to her half-sister (and former cover girl) Patricia.