Michael O'Neill
Acting
1947-05-29 · Montgomery, Alabama, USA
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 · Movie
Bride Hard
2025 · Movie
Happy Face
2025 · Series
Happy's Place
2024 · Series
Tracker
2024 · Series
Air
2023 · Movie
Fire Country
2022 · Series
Echoes
2022 · Series
Outer Range
2022 · Series
Cold Call
2021 · Movie
The Stand at Paxton County
2020 · Movie
Messiah
2020 · Series
Clemency
2019 · Movie
Indivisible
2018 · Movie
The Romanoffs
2018 · Series
Danger One
2018 · Movie
Tom Clancy's Jack Ryan
2018 · Series
The Resident
2018 · Series
S.W.A.T.
2017 · Series
On Yoga: The Architecture of Peace
2017 · Movie
Shooter
2016 · Series
This Is Us
2016 · Series
11.22.63
2016 · Series
Manhattan
2014 · Series
Extant
2014 · Series
The Grim Sleeper
2014 · Movie
Dallas Buyers Club
2013 · Movie
Rectify
2013 · Series
Bates Motel
2013 · Series
Vegas
2012 · Series
Scandal
2012 · Series
J. Edgar
2011 · Movie
Law & Order: LA
2010 · Series
Rizzoli & Isles
2010 · Series
The Glades
2010 · Series
Green Zone
2010 · Movie
Flying Lessons
2010 · Movie
FlashForward
2009 · Series
NCIS: Los Angeles
2009 · Series
Nothing but the Truth
2008 · Movie
Leverage
2008 · Series
A Quiet Little Marriage
2008 · Movie
The Mentalist
2008 · Series
Fringe
2008 · Series
Sons of Anarchy
2008 · Series
Crazy
2008 · Movie
Transformers
2007 · Movie
Army Wives
2007 · Series
The Nine
2006 · Series
The Unit
2006 · Series
Commander in Chief
2005 · Series
Ghost Whisperer
2005 · Series
Criminal Minds
2005 · Series
Close to Home
2005 · Series
Prison Break
2005 · Series
Grey's Anatomy
2005 · Series
Numb3rs
2005 · Series
Around the Bend
2004 · Movie
Boston Legal
2004 · Series
LAX
2004 · Series
American Crime
2004 · Movie
NCIS
2003 · Series
Secondhand Lions
2003 · Movie
Seabiscuit
2003 · Movie
Dreamcatcher
2003 · Movie
The Emperor's Club
2002 · Movie
Without a Trace
2002 · Series
CSI: Miami
2002 · Series
24
2001 · Series
Crossing Jordan
2001 · Series
Traffic
2000 · Movie
The Legend of Bagger Vance
2000 · Movie
Boston Public
2000 · Series
Roswell
1999 · Series
The West Wing
1999 · Series
ATF
1999 · Movie
The Mod Squad
1999 · Movie
Dancer, Texas Pop. 81
1998 · Movie
Virtual Obsession
1998 · Movie
Standoff
1998 · Movie
Ally McBeal
1997 · Series
The Shining
1997 · Series
The Practice
1997 · Series
Millennium
1996 · Series
The Sunchaser
1996 · Movie
JAG
1995 · Series
Bushwhacked
1995 · Movie
Awake to Danger
1995 · Movie
Beyond Betrayal
1994 · Movie
ER
1994 · Series
Chicago Hope
1994 · Series
One West Waikiki
1994 · Series
Blind Justice
1994 · Movie
Victim of Love: The Shannon Mohr Story
1993 · Movie
Diagnosis: Murder
1993 · Series
The X-Files
1993 · Series
For Their Own Good
1993 · Movie
Lorenzo's Oil
1992 · Movie
Jennifer Eight
1992 · Movie
The Gun in Betty Lou's Handbag
1992 · Movie
An Unremarkable Life
1989 · Movie
Sea of Love
1989 · Movie
Ghost Story
1981 · Movie