Michael O'Neill
Acting
101 titles
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.
Filmography
War of the Worlds
2025
Bride Hard
2025
Happy Face
2025
Happy's Place
2024
Tracker
2024
Air
2023
Fire Country
2022
Echoes
2022
Outer Range
2022
Cold Call
2021
The Stand at Paxton County
2020
Messiah
2020
Clemency
2019
Indivisible
2018
The Romanoffs
2018
Danger One
2018
Tom Clancy's Jack Ryan
2018
The Resident
2018
S.W.A.T.
2017
Shooter
2016
This Is Us
2016
11.22.63
2016
Manhattan
2014
Extant
2014
The Grim Sleeper
2014
Dallas Buyers Club
2013
Rectify
2013
Bates Motel
2013
Vegas
2012
Scandal
2012
J. Edgar
2011
Law & Order: LA
2010
Rizzoli & Isles
2010
The Glades
2010
Green Zone
2010
Flying Lessons
2010
FlashForward
2009
NCIS: Los Angeles
2009
Nothing But the Truth
2008
Leverage
2008
A Quiet Little Marriage
2008
The Mentalist
2008
Fringe
2008
Sons of Anarchy
2008
Crazy
2008
Transformers
2007
Army Wives
2007
The Nine
2006
The Unit
2006
Commander in Chief
2005
Ghost Whisperer
2005
Criminal Minds
2005
Close to Home
2005
Prison Break
2005
Grey's Anatomy
2005
Numb3rs
2005
Around the Bend
2004
Boston Legal
2004
LAX
2004
American Crime
2004
NCIS
2003
Secondhand Lions
2003
Seabiscuit
2003
Dreamcatcher
2003
Without a Trace
2002
CSI: Miami
2002
24
2001
Crossing Jordan
2001
Traffic
2000
The Legend of Bagger Vance
2000
Boston Public
2000
Roswell
1999
The West Wing
1999
ATF
1999
The Mod Squad
1999
Dancer, Texas Pop. 81
1998
Virtual Obsession
1998
Standoff
1998
Ally McBeal
1997
The Shining
1997
The Practice
1997
Millennium
1996
The Sunchaser
1996
JAG
1995
Bushwhacked
1995
Awake to Danger
1995
Beyond Betrayal
1994
ER
1994
Chicago Hope
1994
One West Waikiki
1994
Blind Justice
1994
Victim of Love: The Shannon Mohr Story
1993
Diagnosis: Murder
1993
The X-Files
1993
For Their Own Good
1993
Lorenzo's Oil
1992
Jennifer Eight
1992
The Gun in Betty Lou's Handbag
1992
An Unremarkable Life
1989
Sea of Love
1989
Ghost Story
1981