Michael O'Neill
From Wikipedia, the free encyclopedia. Michael O'Neill (born May 29, 1951) is an American actor. With a career stretching through three decades, he usually portrays senior law enforcement or military officers. He is perhaps best known for his role as Special agent Ron Butterfield, the head of President Josiah Bartlet's Secret Service detail, on The West Wing. He played CTU Administrative Director Richard Walsh in the first two episodes of 24. He played Sgt. Maj. Ron Cheals in the CBS action-drama series The Unit. He starred in the Season Six 2 part Finale of Grey's Anatomy as the broken widower who holds the hospital hostage with a 9mm while pursuing the doctors responsible for unplugging his wife. His most notable film performances occur in Seabiscuit, Secondhand Lions, Transformers, Dancer, Texas Pop 81, Traffic, Sea of Love, A Quiet Little Marriage, Nothing But the Truth, and Green Zone. O'Neill graduated from Auburn University in 1974. After attending Auburn he spent time under the tutelage of actor Will Geer and his daughter, Ellen, at Theatricum Botanicum in Los Angeles before moving to New York to pursue his career there.
100 acting credits
Acting · 100
Grey's Anatomy
2005
NCIS
2003
The Mentalist
2008
Criminal Minds
2005
S.W.A.T.
2017
Tracker
2024
CSI: Miami
2002
Prison Break
2005
24
2001
Tom Clancy's Jack Ryan
2018
The X-Files
1993
NCIS: Los Angeles
2009
JAG
1995
ER
1994
Sons of Anarchy
2008
Without a Trace
2002
Fringe
2008
The West Wing
1999
War of the Worlds
2025
The Resident
2018
Diagnosis: Murder
1993
Ghost Whisperer
2005
Crossing Jordan
2001
This Is Us
2016
Scandal
2012
Boston Legal
2004
Rizzoli & Isles
2010
The Practice
1997
Numb3rs
2005
Chicago Hope
1994
Army Wives
2007
Fire Country
2022
Millennium
1996
Close to Home
2005
The Unit
2006
Boston Public
2000
Leverage
2008
Bates Motel
2013
Shooter
2016
Roswell
1999
Ally McBeal
1997
Law & Order: LA
2010
The Glades
2010
Outer Range
2022
FlashForward
2009
Manhattan
2014
Commander in Chief
2005
Extant
2014
Rectify
2013
11.22.63
2016
The Romanoffs
2018
Happy's Place
2024
LAX
2004
Messiah
2020
Air
2023
The Shining
1997
One West Waikiki
1994
Transformers
2007
Happy Face
2025
Dallas Buyers Club
2013
The Nine
2006
Traffic
2000
Echoes
2022
Dreamcatcher
2003
Seabiscuit
2003
Bride Hard
2025
Sea of Love
1989
Green Zone
2010
The Legend of Bagger Vance
2000
Secondhand Lions
2003
J. Edgar
2011
Lorenzo's Oil
1992
Bushwhacked
1995
Jennifer Eight
1992
Ghost Story
1981
The Sunchaser
1996
Nothing But the Truth
2008
Clemency
2019
Crazy
2008
The Grim Sleeper
2014
Around the Bend
2004
The Mod Squad
1999
Flying Lessons
2010
Danger One
2018
Blind Justice
1994
The Gun in Betty Lou's Handbag
1992
Virtual Obsession
1998
Indivisible
2018
Standoff
1998
Victim of Love: The Shannon Mohr Story
1993
For Their Own Good
1993
An Unremarkable Life
1989
American Crime
2004
ATF
1999
The Stand at Paxton County
2020
Dancer, Texas Pop. 81
1998
Beyond Betrayal
1994
Awake to Danger
1995
A Quiet Little Marriage
2008
Cold Call
2021