Colm J. Meaney (; Irish: Colm Ó Maonaigh; born 30 May 1953) is an Irish actor best known for playing Miles O'Brien in Star Trek: The Next Generation (1987–1994) and Star Trek: Deep Space Nine (1993–1999). He has guest-starred on many TV shows including Law & Order and The Simpsons, and starred as Thomas C. Durant on Hell on Wheels (2011–2016).