Mark O'BrienMark 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).FilmographyThe Outer Threat (2026)Nuremberg (2025)The Copenhagen Test (2025)The Sticky (2024)61st Street (2022)Blue Bayou (2021)Ready or Not (2019)City on a Hill (2019)The Darkest Minds (2018)The Front Runner (2018)Parallel (2018)Arrival (2016)The Last Tycoon (2016)Republic of Doyle (2010)