Mark O'Brien
- Birth Date
- 5/7/1984
- Birth Place
- St. Johns, Newfoundland, Canada
- Known For
- Acting
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).
