Mark O'Brien

Actor and filmmaker Mark O'Brien is best known to Canadian audiences for his role as "Des Courtney" on the long-running CBC award-winning comedy-drama TV series Republic of Doyle. He's twice been nominated for a Canadian Comedy Award for Best Male Performance.

In the U.S., O'Brien was cast in the second season of the AMC drama Halt and Catch Fire. The series is set in the early 1980s, in the halcyon days of the computer tech revolution. O'Brien's character, Tom Rendon is a savvy IT department head at a law firm, who has a passion for gaming.

O'Brien has appeared in several hit series including NBC's Hannibal, where he played a recurring role as "Randall Tier," a psychotic serial killer. He has also been featured on episodes of CTV's Saving Hope, CBC's Murdoch Mysteries and Syfy's Warehouse 13, as well as the new Syfy series Killjoys. In 2010, O'Brien starred in the Sundance Film Festival selection Grown Up Movie Star alongside Orphan Black's Tatiana Maslany.

O'Brien's directorial credits include select episodes of Republic of Doyle, as well as nine short films, including Better People, which showcased in 10 film festivals across Canada and the United States, and Sweetieface, seen in film festivals across the Canada. Both films received critical acclaim, winning multiple awards including Best Short Film at the 2013 and 2014 WorldFest-Houston International Film Festival, Best Emerging Filmmaker at the 2013 Lakeshorts International Film Festival and Best Short Film at the 2013 Atlantic Film Festival. He was recently nominated for another Canadian Comedy Award, this time as Best Director of a television series for his work on Republic of Doyle.

O'Brien starred in Canadian indie films The End of Days, Inc., a dark comedy with a supernatural spin that premiered at the USA Film Festival in Dallas Texas, Len & Company directed by Tim Godsall, and The Dark Stranger alongside Katie Findlay, Enrico Colantoni and Stephen McHattie.

O'Brien holds a Bachelor of Arts from Memorial University of Newfoundland with a major in English Literature. In May 2015 the University awarded him with the Horizon Alumni Award for Best Career Achievement for an alumnus under the age of 35.

Paramount Pictures