Mark O’Brien is a Canadian actor, as well as director. He first acted in a couple of short films. On TV, he debuted on Kids’ CBC. He next appeared in the miniseries Above and Beyond. In the 2010s, he became known for starring as Des Courtney in the Canadian show Republic of Doyle. He reprised his role in Diary of a Deadly P.I. He went on to have guest roles on Murdoch Mysteries, This Hour Has 22 Minutes, Hannibal, and Saving Hope. From 2015-2016, he played Tom Rendon in the AMC series Halt and Catch Fire. He also recently played Max Miner in the US series The Last Tycoon.