Mary McCormack
Acting
76
Acting Credits
Biography
Mary Catherine McCormack is an American actress. She has had leading roles as Justine Appleton on the series Murder One (1995–1997), as Deputy National Security Adviser Kate Harper on The West Wing (2004–2006), as Deputy U.S. Marshal Mary Shannon on In Plain Sight (2008–2012), and as Peggy on the comedy series The Kids Are Alright (2018–2019).
Known For
Filmography
Vicious
2025
as Mother
National Memorial Day Concert
2023
as Self
Heels
2021
as Willie Day
Unpregnant
2020
as Debra Clarke
Treehouse
2019
as Lilith
Still Laugh-In: The Stars Celebrate
2019
as Self
The L Word: Generation Q
2019
as Anne Finley
The Kids Are Alright
2018
as Peggy Cleary
For the People
2018
as Chloe Daniels
25 Words or Less
2018
as Self
25 Words or Less
2018
25 Words or Less
2018
as Mary McCormack
The Crash
2017
as Sarah Schwab
Drone
2017
as Ellen
Alien Code
2017
as Rebecca
Loaded
2017
as Casey
Will & Grace
2017
as Janet
A Country Called Home
2016
as Amanda
An American Girl Story: Maryellen 1955 - Extraordinary Christmas
2016
as Kay Larkin
Chelsea Does
2016
as Herself
Chelsea
2016
as Self
Divorce
2016
as Kathy DeSantis
Angie Tribeca
2016
as Abigail Liukin
Match Game
2016
as Self - Panelist
To Tell the Truth
2016
as Self - Panelist
Scooby-Doo! WrestleMania Mystery
2014
as Ms. Richards (voice)
Escape from Polygamy
2013
as Leann
Welcome to the Family
2013
as Caroline Yoder
Should've Been Romeo
2012
as Ellen
The Unprofessional
2012
as Hilary Pfeiffer-Dunne
House of Lies
2012
as Denna Altshuler
Scandal
2012
as Lisa Elliot
The Newsroom
2012
as Molly Levy
Watch What Happens Live with Andy Cohen
2009
as Self - Guest
Late Night with Jimmy Fallon
2009
as Self
In Plain Sight
2008
as Mary Shannon
1408
2007
as Lilly Enslin
Right at Your Door
2006
as Lexi
For Your Consideration
2006
as Pilgrim Woman
Madison
2005
as Bonnie McCormick
The Late Late Show with Craig Ferguson
2005
as Self
Traffic
2004
as Carole McKay
Dickie Roberts: Former Child Star
2003
as Grace Finney
The Ellen DeGeneres Show
2003
as Self
K Street
2003
as Maggie Morris
Full Frontal
2002
as Linda
World Traveler
2002
as Margaret
K-PAX
2001
as Rachel Powell
High Heels and Low Lifes
2001
as Frances
BigLove
2001
as Phoebe
Law & Order: Criminal Intent
2001
as Mary Shannon
The Broken Hearts Club: A Romantic Comedy
2000
as Anne
Gun Shy
2000
as Gloria Nesstra
Other Voices
2000
as Anna
East of A
2000
as Daphne
The Big Tease
1999
as Monique
Mystery, Alaska
1999
as Donna Biebe
Harvest
1999
as Agent Becka Anslinger
True Crime
1999
as Michelle Ziegler
Getting to Know You
1999
as Leila Lee
The Late Late Show with Craig Kilborn
1999
as Self - Guest
The West Wing
1999
as Kate Harper
Deep Impact
1998
as Andrea Baker
54
1998
as New Year's Eve Wife (uncredited)
The Alarmist
1998
as Sally
Private Parts
1997
as Alison Stern
Colin Fitz
1997
as Moira
Fathers' Day
1997
as Virginia Farrell (uncredited)
Murder One: Diary of a Serial Killer
1997
as Justine Appleton
Backfire!
1995
as Sarah Jackson
Murder One
1995
as Justine Appleton
The Wright Verdicts
1995
as Beth Eckhart
Miracle on 34th Street
1994
as Myrna Foy
ER
1994
as Debbie
The Tonight Show with Jay Leno
1992
Law & Order
1990
as Rickie the Bartender