Mitchell Craig "Mitch" Pileggi (born April 5, 1952) is an American actor, best known for his role as Walter Skinner on The X-Files. He also had a recurring role on Stargate Atlantis as Colonel Steven Caldwell. He appeared in the 2008 film 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).