Michael O'Neill
Biography
Michael O'Neill is an American actor born on May 29, 1947, in Montgomery, Alabama, USA. He has a career spanning over three decades, primarily portraying senior law enforcement or military officers. O'Neill is known for his roles in various television series, including The West Wing, where he played Special agent Ron Butterfield, and The Unit, where he portrayed Sgt. Maj. Ron Cheals. He also appeared in the first two episodes of 24 as CTU Administrative Director Richard Walsh. In addition, O'Neill starred in the Season Six two-part finale of Grey's Anatomy as a broken widower. Throughout his acting career, he has accumulated 103 known credits.
Career overview
Michael O'Neill is an American actor with a career spanning over three decades. He is known for his portrayal of senior law enforcement or military officers in various roles. One of his notable appearances is as Special agent Ron Butterfield in a television series. He also played CTU Administrative Director in the first two episodes of a popular series. Additionally, he portrayed Sgt. Maj. Ron Cheals in a CBS action-drama series.
O'Neill has appeared in numerous other roles throughout his career. He is perhaps best known for his portrayal of a character in a two-part season finale of a medical drama series. In this role, he played a broken widower who holds a hospital hostage in pursuit of the doctors responsible for a specific action. His acting credits include a significant number of roles, with over 100 known credits to his name.
Michael O'Neill's acting career has been marked by his versatility in portraying characters in various settings. His ability to take on different roles has contributed to his extensive body of work in the entertainment industry. His performances have been recognized and appreciated by audiences and critics alike, solidifying his position as a seasoned actor with a long and distinguished career.
Ask the Vault
Ask anything about Michael O'Neill.
Frequent co-stars
Career timeline
Full filmography
- War of the Worlds (2025) as Secretary of Defense Walter Crystal
- Bride Hard (2025) as Frank
- Happy Face (2025) as D.A. Craig Calloway
- Tracker (2024) as Buck Avery
- Happy's Place (2024) as Jim Jackoway
- Air (2023) as Joe Dean
- Fire Country (2022) as Harlan Denbo
- Outer Range (2022) as Judge Pettigrew
- Echoes (2022) as Victor McCleary
- Cold Call (2021) as Christian
- Messiah (2020) as Cameron Collier
- The Stand at Paxton County (2020) as Dell Connelly
- Clemency (2019) as Chaplain David Kendricks
- The Resident (2018) as Joshua Williams
- Tom Clancy's Jack Ryan (2018) as Senator Mitchell Chapin
- The Romanoffs (2018) as Ron Hopkins
- Danger One (2018) as Beckwith
- Indivisible (2018) as Chaplain Rogers
- S.W.A.T. (2017) as Carl Luca
- On Yoga: The Architecture of Peace (2017) Producer
- This Is Us (2016) as Arlo
- Shooter (2016) as Ray Brooks
- 11.22.63 (2016) as Arliss Price
- Extant (2014) as Alan Sparks
- Manhattan (2014) as Psychiatrist
- The Grim Sleeper (2014) as Detective Simms
- Bates Motel (2013) as Nick Ford
- Dallas Buyers Club (2013) as Richard Barkley
- Rectify (2013) as Senator Roland Foulkes
- Scandal (2012) as Lonnie Mencken
- Vegas (2012) as Mayor Ted Bennett
- J. Edgar (2011) as Senator McKellar
- Rizzoli & Isles (2010) as Jonathan McKnight
- The Glades (2010) as Trent Staley
- Law & Order: LA (2010) as Jeb Monroe
- Green Zone (2010) as Colonel Bethel
- Flying Lessons (2010) as Chief Dobbs
- NCIS: Los Angeles (2009) as Ret. U.S. Army General Richard Collins
- FlashForward (2009) as CIA Director Keller
- The Mentalist (2008) as Sheriff Nelson
- Sons of Anarchy (2008) as Anthony Franklin
- Fringe (2008) as Sheriff Velchik
- Leverage (2008) as Judge Roy
- Nothing but the Truth (2008) as CIA Director
- Crazy (2008) as Ralph Christianson
- A Quiet Little Marriage (2008) as Bruce
- Army Wives (2007) as Reverend Bankerd
- Transformers (2007) as Tom Banacheck
- The Unit (2006) as Ron Cheals
- The Nine (2006) as Pete Burton
- Grey's Anatomy (2005) as Gary Clark
- Criminal Minds (2005) as Det. Yarbough
- Prison Break (2005) as Herb Stanton
- Ghost Whisperer (2005) as Nolan
- Numb3rs (2005) as Boyd Keene
- Close to Home (2005) as Don Wheeler
- Commander in Chief (2005) as Congressman Wilcox
- Boston Legal (2004) as Dr. Robert McLean
- LAX (2004) as Alonso Mathews
- Around the Bend (2004) as Cowboy
- American Crime (2004) as Sheriff Smyth
- NCIS (2003) as Riley McCallister
- Dreamcatcher (2003) as Gen. Matheson
- Secondhand Lions (2003) as Ralph
- Seabiscuit (2003) as Mr. Pollard
- CSI: Miami (2002) as Jerry Blackburn
- Without a Trace (2002) as Thomas Shannon
- The Emperor's Club (2002) Co-Producer
- 24 (2001) as Richard Walsh
- 24 (2001) as Richard Welsh
- Crossing Jordan (2001) as Chris Benz
- Boston Public (2000) as Dr. Bernard Colbert
- Traffic (2000) as Lawyer Rodman
- The Legend of Bagger Vance (2000) as O.B. Keeler
- The West Wing (1999) as Ron Butterfield
- Roswell (1999) as Philip Evans
- ATF (1999) as ATF Asst. Director Ben Walker
- The Mod Squad (1999) as Greene
- Dancer, Texas Pop. 81 (1998) as Mr. Lusk
- Virtual Obsession (1998)
- Standoff (1998) as Cult Leader (Voice)
- The Practice (1997) as Judge Robert Temple
- Ally McBeal (1997) as Dr. Colbert
- The Shining (1997) as Daniel Edwards (uncredited)
- Millennium (1996) as County Prosecutor Calvin Smith
- The Sunchaser (1996) as Agent Moreland
- JAG (1995) as Commander Bradley
- Bushwhacked (1995) as Jon Jordan
- Awake to Danger (1995) as Detective Brickman
- ER (1994) as Col. Ken Kilner
- Chicago Hope (1994) as Bill Wyzinski
- One West Waikiki (1994)
- Beyond Betrayal (1994) as Ray Pasquerello
- Blind Justice (1994) as Spencer Heymen
- The X-Files (1993) as Patrol Captain Van Gelder
- Diagnosis: Murder (1993) as Sheriff Buck O'Hara
- For Their Own Good (1993) as Clark Thompson
- Victim of Love: The Shannon Mohr Story (1993) as Dick Britton
- Lorenzo's Oil (1992) as School Psychologist
- Jennifer Eight (1992) as Serato
- The Gun in Betty Lou's Handbag (1992) as Jergens
- Sea of Love (1989) as Raymond Brown
- An Unremarkable Life (1989) as Michael
- Ghost Story (1981) as Churchill