Mary McCormack
Known for: Acting
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).
Filmography
Series
Law & Order
Rickie the Bartender
1990
Series
Watch What Happens Live with Andy Cohen
Self - Guest
2009
Series
Law & Order: Criminal Intent
Mary Shannon
2001
Series
The Pitt
Dr. Linda Conley
2025
Series
The Late Late Show with Craig Ferguson
Self
2005
Series
The West Wing
Kate Harper
1999
Series
Scandal
Lisa Elliot
2012
Series
Jimmy Kimmel Live!
Self
2003
Series
ER
Debbie
1994
Series
Tony Awards
Self - Nominee
1956
Series
The Tonight Show with Jay Leno
1992
Series
The Ellen DeGeneres Show
Self
2003
Series
25 Words or Less
Self
2018
Series
25 Words or Less
2018
Series
25 Words or Less
Mary McCormack
2018
Series
Angie Tribeca
Abigail Liukin
2016
Series
The Newsroom
Molly Levy
2012
Series
Late Night with Jimmy Fallon
Self
2009
Series
In Plain Sight
Mary Shannon
2008
Film
Deep Impact
Andrea Baker
1998
Series
Chelsea
Self
2016
Series
House of Lies
Denna Altshuler
2012
Series
Will & Grace
Janet
2017
Series
To Tell the Truth
Self - Panelist
2016
Series
Murder One
Justine Appleton
1995
Film
1408
Lilly Enslin
2007
Series
Match Game
Self - Panelist
2016
Series
For the People
Chloe Daniels
2018
Series
The Late Late Show with Craig Kilborn
Self - Guest
1999
Series
The L Word: Generation Q
Anne Finley
2019
Series
Divorce
Kathy DeSantis
2016
Film
K-PAX
Rachel Powell
2001
Film
True Crime
Michelle Ziegler
1999
Film
Miracle on 34th Street
Myrna Foy
1994
Film
Vicious
Mother
2025
Film
54
New Year's Eve Wife (uncredited)
1998
Series
Heels
Willie Day
2021
Film
Private Parts
Alison Stern
1997
Series
Traffic
Carole McKay
2004
Series
K Street
Maggie Morris
2003
Film
Gun Shy
Gloria Nesstra
2000
Film
Fathers' Day
Virginia Farrell (uncredited)
1997
Series
The Kids Are Alright
Peggy Cleary
2018
Film
Full Frontal
Linda
2002
Film
Mystery, Alaska
Donna Biebe
1999
Film
Drone
Ellen
2017
Film
Scooby-Doo! WrestleMania Mystery
Ms. Richards (voice)
2014
Series
Welcome to the Family
Caroline Yoder
2013
Film
Dickie Roberts: Former Child Star
Grace Finney
2003
Film
Treehouse
Lilith
2019
Film
For Your Consideration
Pilgrim Woman
2006
Series
Loaded
Casey
2017
Series
The Wright Verdicts
Beth Eckhart
1995
Film
The Crash
Sarah Schwab
2017
Film
Unpregnant
Debra Clarke
2020
Film
The Broken Hearts Club: A Romantic Comedy
Anne
2000
Film
High Heels and Low Lifes
Frances
2001
Film
Backfire!
Sarah
1995
Film
Alien Code
Rebecca
2017
Film
Still Laugh-In: The Stars Celebrate
Self
2019
Series
Chelsea Does
Herself
2016
Film
Right at Your Door
Lexi
2006
Film
The Big Tease
Monique
1999
Film
National Memorial Day Concert
Self
2023
Film
The Alarmist
Sally
1998
Film
BigLove
Phoebe
2001
Film
Harvest
Agent Becka Anslinger
1999
Film
Escape from Polygamy
Leann
2013
The Unprofessional
Hilary Pfeiffer-Dunne
2012
Film
Madison
Bonnie McCormick
2005
Film
Murder One: Diary of a Serial Killer
Justine Appleton
1997
Film
Colin Fitz
Moira
1997
Film
Other Voices
Anna
2000
Film
A Country Called Home
Amanda
2016
Film
World Traveler
Margaret
2002
Film
An American Girl Story: Maryellen 1955 - Extraordinary Christmas
Kay Larkin
2016
Film
Should've Been Romeo
Ellen
2012
Film
Getting to Know You
Leila Lee
1999
East of A
Daphne
2000