Mitchell Craig "Mitch" Pileggi (born April 5, 1952) is an American actor. He was born in Portland, Oregon. Pileggi is best known for his role as Walter Skinner on "The X-Files". He had a recurring role on "Stargate Atlantis" as Colonel Steven Caldwell. He appeared in the 2008 movie "Flash of Genius". In 2008, he began a recurring role as Ernest Darby in "Sons of Anarchy". He starred as Harris Ryland in the TNT revival of "Dallas" (2012–2014).