| Year | Title | Role | Notes |
|---|
| 1979 | Before and After | Woman Bather | Television film |
| 1983 | Reggie | Joan Reynolds | Main cast |
| Teachers Only | Shari | Main cast (season 2) |
| 1984 | The Facts of Life | Ellen Slater | Episode: "Next Door" |
| Maximum Security | Dr. Allison Brody | 3 episodes |
| Single Bars, Single Women | Virge | Television film |
| Piaf | Marlene Dietrich |
| 1986 | A Fight for Jenny | Valerie Thomas |
| 1986–91 | Designing Women | Charlene Frazier-Stillfield | Main cast |
| 1987 | Place at the Table | Susan Singer | Television film |
| 1991 | A Seduction in Travis County | Karen |
| Locked Up: A Mother's Rage | Cathy |
| 1992 | Overkill: The Aileen Wuornos Story | Aileen Wuornos |
| Just My Imagination | Pally Thompson |
| 1993 | Batman: The Animated Series | Helen Ventrix (voice) | Episode: "See No Evil" [1] |
| 1994 | Scarlett | Sally Brewton | Miniseries, recurring role |
| The Yarn Princess | Margaret Thomas | Television film |
| 1995 | A Stranger in Town | Rose |
| 1995–96 | High Society | Elinore 'Ellie' Walker | Main cast |
| 1997 | Hey Arnold! | Reba Heyerdahl (voice) | Episode: "Phoebe Cheats" [1] |
| Undue Influence | Dana Colby | Television film |
| 1998 | Style & Substance | Chelsea Stevens | Main cast |
| A Change of Heart | Elaine Mitchell | Television film |
| 2000 | The Man Who Came to Dinner | Lorraine Sheldon |
| 2000–01 | Frasier | Lana Gardner | 7 episodes |
| 2000–03 | Static Shock | Maggie Foley (voice) | 3 episodes [1] |
| 2000–04 | The District | Detective Sherry Regan | Recurring role |
| 2001 | The Oblongs | Pickles Oblong (voice) | Main role |
| 2002–03 | In-Laws | Marlene Pellet |
| 2002–07 | Kim Possible | Ann Possible (voice) | Recurring role |
| 2004 | Audrey's Rain | Audrey Walker | Television film |
| Killer Instinct: From the Files of Agent Candice DeLong | Candice DeLong |
| A Very Married Christmas | Ellen Griffin |
| Hey Arnold! | Reba Heyerdahl (voice) | Episode: "Phoebe's Little Problem/Grandpa's Packard" |
| 2004–05 | Center of the Universe | Kate Barnett | Main cast |
| 2006–07 | 24 | Martha Logan | Main cast (season 5); guest (season 6) |
| 2007–09 | Samantha Who? | Regina Newly | Main cast |
| 2008 | American Dad! | Miriam Bullock (voice) | Episode: "One Little Word" |
| 2009 | Woke Up Dead | Meryl Greene | Episode: "Mother's Day" |
| 2010 | Psych | Gillian Tucker | Episode: "Chivalry Is Not Dead...But Someone Is" |
| 2010–11 | Hawaii Five-0 | Governor Pat Jameson | 4 episodes |
| 2011 | $#*! My Dad Says | Rosemary Penworth | 4 episodes |
| William & Catherine: A Royal Romance | Camilla, Duchess of Cornwall | Television film |
| 2011–12 | Harry's Law | Roseanna Remmick | Recurring role (season 2) |
| 2013 | Hot in Cleveland | Bess | Episode: "Conoga Falls" |
| Call Me Crazy: A Five Film | Claire | Television film, segment: "Allison" |
| When Calls the Heart | Frances | Television film |
| 2014 | Halt and Catch Fire | LouLu Lutherford | Episode: "High Plains Hardware" |
| Getting On | Arlene Willy-Weller | 2 episodes |
| 2014–15 | Sirens | Nora Farrell | 3 episodes |
| 2015 | The McCarthys | Lydia | Episode: "Gerard's Engagement Party" |
| Fargo | Floyd Gerhardt | Main cast (season 2) |
| 2015–16 | Girlfriends' Guide to Divorce | Katherine Miller | Recurring role (season 2) |
| 2016 | Bad Internet | President Powers | Episode: "The President Goes Viral" |
| 2017 | Angie Tribeca | Carnie | Episode: "License to Drill" |
| Veep | Mrs. Walsh | Episode: "Judge" |
| 2017–19 | Legion | Melanie Bird | Main cast (seasons 1–2); guest (season 3) |
| 2018 | A Shoe Addict's Christmas | Charlie / Guardian Angel | Television film |
| 2018–19 | Dirty John | Arlane Hart | Recurring role (season 1) |
| 2018–21 | Big Mouth | Depression Kitty (voice) | Recurring role |
| 2019 | Arrested Development | Mimi | 2 episodes |
| Watchmen | Agent Laurie Blake | Main cast |
| Mad About You | Chelsea Stevens-Kobolakis | Episode: "Real Estate for Beginners" |
| 2021 | Mare of Easttown | Helen Fahey | Miniseries, main role |
| 2021–present | Hacks | Deborah Vance | Lead role |
| 2022 | Ghostwriter | Charlotte (voice) | 2 episodes |
| 2024 | Saturday Night Live | Herself (host) | Episode: "Jean Smart/Jelly Roll" |
| 2025 | The Studio | Herself | Episode: "The Golden Globes" |