| Year | Title | Role | Notes |
| 1978 | Ryan's Hope | Ryan's bar patron | |
| 1978–79 | Love of Life | Amy Russell | Series regular |
| 1981 | As the World Turns | Hayley Wilson Hollister | Series regular, role from January 2, 1981, to December 1, 1981 |
| 1984 | Threesome | Laura Shaper | TV film |
| 1984 | The Streets | Jeannie | TV film |
| 1985 | Moonlighting | Jillian Armstrong | Episode: "Knowing Her" |
| 1986 | A Winner Never Quits | Nora | TV film |
| 1986 | Liberty | Moya Trevor | TV film |
| 1986–87 | Magnum, P.I. | Cynthia Farrell | Episodes: "L.A." and "Out of Sync" |
| 1987 | Sweet Surrender | Georgia Holden | Series regular, 6 episodes |
| 1988 | Thirtysomething | Eve | Episode: "South by Southeast" |
| 1988–91 | China Beach | Colleen McMurphy | Series regular, 62 episodes |
| 1990 | A Promise to Keep | Jane Goodrich | TV film |
| 1992 | Cheers | Susan Metheny | Episode: "Love Me, Love My Car" |
| 1993 | Wild Palms | Grace Wyckoff | TV miniseries, 5 episodes |
| 1993 | Donato and Daughter | Lieutenant Dena Donato | TV film |
| 1994 | The Enemy Within | Betsy Corcoran | TV film |
| 1994 | Texan | Anne Williams | TV short |
| 1995 | Fallen Angels | Helen Fiske | Episode: "Good Housekeeping" |
| 1995 | Choices of the Heart: The Margaret Sanger Story | Margaret Sanger | TV film |
| 1996 | For Hope | Hope Altman | TV film |
| 1996 | Wing Commander Academy | Gwen Archer Bowman | Voice, 13 episodes |
| 1996–2000 | Superman: The Animated Series | Lois Lane | Voice, 44 episodes |
| 1997 | Duckman | Dr. Susan Fox | Voice, episode: "Role with It" |
| 1997 | True Women | Sarah Ashby McClure | TV film |
| 1997 | Spy Game | Honey Trapp | Episode: "Dead and Gone, Honey" |
| 1998 | The Patron Saint of Liars | Rose Cleardon Abbott | TV film |
| 1998 | Rescuers: Stories of Courage: Two Couples | Johtje Vos | TV film |
| 1999 | Resurrection | Clare Miller | TV film |
| 1999 | Sirens | Sally Rawlings | TV film |
| 1999 | Shake, Rattle and Roll: An American Love Story | Elaine Gunn | TV film |
| 2001 | Family Law | Mary Sullivan | Episode: "Safe At Home" |
| 2001 | Final Jeopardy | Alexandra Cooper | TV film, also co-executive producer |
| 2001–02 | Pasadena | Catherine McAllister | Series regular, 13 episodes |
| 2002 | Conviction | Martha | TV film |
| 2002–03 | Presidio Med | Dr. Rae Brennan | Series regular, 13 episodes |
| 2003 | A Time to Remember | Britt Calhoun | TV film |
| 2003–05 | Justice League | Lois Lane, Loana | Voice, 7 episodes |
| 2004 | Baby for Sale | Nathalie Johnson | TV film |
| 2004 | Law & Order: Special Victims Unit | Carolyn Spencer | Episode: "Obscene" |
| 2004 | Boston Legal | Samantha Fleming | Episode: "Truth Be Told" |
| 2005 | Kojak | Kate McNeil | Episodes: "All Bets Are Off, Parts I and II" |
| 2005–06 | Related | Francesca Sorelli | Episodes: "Francesca" and "The Move" |
| 2006 | The L Word | Senator Barbara Grisham | Episode: "Light My Fire" |
| 2006 | Battlestar Galactica | Sesha Abinell | Episode: "Sacrifice" |
| 2006 | The Woman with the Hungry Eyes | Theda Bara | Voice |
| 2006 | Kidnapped | Ellie Cain | Series regular, 13 episodes |
| 2007 | The Batman | Lois Lane | Voice, episode: "The Batman/Superman Story" |
| 2007–10, 2012 | Desperate Housewives | Katherine Mayfair | Series regular (Seasons 4–6), Special guest star (Season 8)55 episodes |