Mark O'Brien
Known for ActingBorn 1984-05-07 St. Johns, Newfoundland, Canada
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).
Known for
Arrival
2016 · as Captain Marks
Ready or Not
2019 · as Alex
Nuremberg
2025 · as Colonel John Amen
How It Ends
2018 · as Jeremiah
The Darkest Minds
2018 · as Rob Meadows
Marriage Story
2019 · as Carter Mitchum
Bad Times at the El Royale
2018 · as Larsen Rogers
Anon
2018 · as Cyrus Frear
Kin
2018 · as Jake
The Front Runner
2018 · as Billy Shore
Shadow of God
2025 · as Mason Harper
The Voices of Our Mother
2026 · as William
Seven Veils
2025 · as Paul
Parallel
2018 · as Josh
Blue Bayou
2021 · as Ace
The Righteous
2021 · as Aaron Smith
Little One
How to Plan an Orgy in a Small Town
2015 · as Bruce Buck