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.
Born: 29 May 1947
Played In
War of the Worlds
Secretary of Defense Walter Crystal
Bride Hard
Frank
Happy Face
D.A. Craig Calloway
Happy's Place
Jim Jackoway
Tracker
Buck Avery
Air
Joe Dean
Fire Country
Harlan Denbo
Echoes
Victor McCleary
Outer Range
Judge Pettigrew
Cold Call
Christian
The Stand at Paxton County
Dell Connelly
Messiah
Cameron Collier
Clemency
Chaplain David Kendricks
Indivisible
Chaplain Rogers
The Romanoffs
Ron Hopkins
Danger One
Beckwith
Tom Clancy's Jack Ryan
Senator Mitchell Chapin
The Resident
Joshua Williams
S.W.A.T.
Carl Luca
Shooter
Ray Brooks
This Is Us
Arlo
11.22.63
Arliss Price
Manhattan
Psychiatrist
Extant
Alan Sparks
The Grim Sleeper
Detective Simms
Dallas Buyers Club
Richard Barkley
Rectify
Senator Roland Foulkes
Bates Motel
Nick Ford
Vegas
Mayor Ted Bennett
Scandal
Lonnie Mencken
J. Edgar
Senator McKellar
Law & Order: LA
Jeb Monroe
Rizzoli & Isles
Jonathan McKnight
The Glades
Trent Staley
Green Zone
Colonel Bethel
Flying Lessons
Chief Dobbs
FlashForward
CIA Director Keller
NCIS: Los Angeles
Ret. U.S. Army General Richard Collins
Nothing But the Truth
CIA Director
Leverage
Judge Roy
A Quiet Little Marriage
Bruce
The Mentalist
Sheriff Nelson
Fringe
Sheriff Velchik
Sons of Anarchy
Anthony Franklin
Crazy
Ralph Christianson
Transformers
Tom Banacheck
Army Wives
Reverend Bankerd
The Nine
Pete Burton
The Unit
Ron Cheals
Commander in Chief
Congressman Wilcox
Ghost Whisperer
Nolan
Criminal Minds
Det. Yarbough
Close to Home
Don Wheeler
Prison Break
Herb Stanton
Grey's Anatomy
Gary Clark
Numb3rs
Boyd Keene
Around the Bend
Cowboy
Boston Legal
Dr. Robert McLean
LAX
Alonso Mathews
American Crime
Sheriff Smyth
NCIS
Riley McCallister
Secondhand Lions
Ralph
Seabiscuit
Mr. Pollard
Dreamcatcher
Gen. Matheson
Without a Trace
Thomas Shannon
CSI: Miami
Jerry Blackburn
24
Richard Welsh
24
Richard Walsh
Crossing Jordan
Chris Benz
Traffic
Lawyer Rodman
The Legend of Bagger Vance
O.B. Keeler
Boston Public
Dr. Bernard Colbert
Roswell
Philip Evans
The West Wing
Ron Butterfield
ATF
ATF Asst. Director Ben Walker
The Mod Squad
Greene
Dancer, Texas Pop. 81
Mr. Lusk
Virtual Obsession
Standoff
Cult Leader (Voice)
Ally McBeal
Dr. Colbert
The Shining
Daniel Edwards (uncredited)
The Practice
Judge Robert Temple
Millennium
County Prosecutor Calvin Smith
The Sunchaser
Agent Moreland
JAG
Commander Bradley
Bushwhacked
Jon Jordan
Awake to Danger
Detective Brickman
Beyond Betrayal
Ray Pasquerello
ER
Col. Ken Kilner
Chicago Hope
Bill Wyzinski
One West Waikiki
Blind Justice
Spencer Heymen
Victim of Love: The Shannon Mohr Story
Dick Britton
Diagnosis: Murder
Sheriff Buck O'Hara
The X-Files
Patrol Captain Van Gelder
For Their Own Good
Clark Thompson
Lorenzo's Oil
School Psychologist
Jennifer Eight
Serato
The Gun in Betty Lou's Handbag
Jergens
An Unremarkable Life
Michael
Sea of Love
Raymond Brown
Ghost Story
Churchill