Mark O'Brien (born May 7th, 1984) is a Canadian actor and director. He is best known for playing the role of Des Courtney in Republic of Doyle (2010) and Tom Rendon in Halt and Catch Fire (2014).

Filmography

• 2026The Outer Threat — Daniel Ashford
• 2026The Voices of Our Mother — William, Director, Writer
• 2025Nuremberg — Colonel John Amen
• 2025Seven Veils — Paul
• 2025Shadow of God — Mason Harper
• The Copenhagen Test — Edmund Cobb
• 2025The Memory Keeper — Elizeus Carrier
• 2025Topper — Topper
• The Sticky — Charlie
• 61st Street — Officer Logan
• 2021Blue Bayou — Ace
• 2021The Righteous — Aaron Smith, Executive Producer, Director, Writer
• Perry Mason — Thomas Milligan
• Your Honor — Father Jay
• City on a Hill — Jimmy Ryan
• 2019Goalie — Terry Sawchuk, Executive Producer
• 2019Hammer — Chris Davis
• 2019Marriage Story — Carter Mitchum
• 2019Ready or Not — Alex
• 2019State Like Sleep — Darren
• 2018Anon — Cyrus Frear
• 2018Bad Times at the El Royale — Larsen Rogers
• 2018How It Ends — Jeremiah
• 2018Kin — Jake
• 2018Parallel — Josh
• 2018The Darkest Minds — Rob Meadows
• 2018The Front Runner — Billy Shore
• The Last Tycoon — Max Miner
• 2016Arrival — Captain Marks
• 2016The Dark Stranger — Mark
• 2016Wanderer — Eric, Director, Producer
• 2015Dennis — Dennis, Producer
• 2015End of Days, Inc. — Jason
• 2015How to Plan an Orgy in a Small Town — Bruce Buck
• Killjoys — Grayson Hicks
• Halt and Catch Fire — Tom Rendon
• Hannibal — Randall Tier
• 2013Sweetieface — Sam, Director, Producer, Editor
• 2012Beat Down — Michael
• 2011Kathy — Director
• 2010Brad — Brad, Producer, Editor
• 2010Grown Up Movie Star — Will
• Republic of Doyle — Des Courtney
• 2010Snarbuckled — Jacob O'Higgins
• 2009Cut from the Same Cloth — Jack Cochrane
• 2009Mum's the Word — Curtis
• 2009Quiet at Dawn — Watts
• Warehouse 13 — Jerry Hoffler
• 2008Epilogue — Henry
• 2008Heartless Disappearance Into Labrador Seas — Charlie
• 2008Pretty Girls — Director, Writer, Editor, Cinematography
• 2008The Four Horsemen — Eric Rollins
• 2008The One That Got Away — Tommy Palchek
• Better People — John, Director, Writer, Editor
• Good in the Room — Charlie, Writer, Executive Producer
• Little One
• Nice People — Director
• Soma — Paul

Appearances as themselves (1)

• The Kelly Clarkson Show — Self