Samuel Atkinson "Sam" Waterston (born November 15, 1940) is an American actor, and sometimes also a producer and director. Among other roles, he is known for his Academy Award nomination for his role as Sydney Schanberg in the 1984 film The Killing Fields and for his role as Jack McCoy in the NBC television series Law & Order, for which he received Golden Globe and Screen Actors Guild Awards. He has been nominated for numerous Golden Globe, Screen Actors Guild, BAFTA, and Emmy Awards, appearing in more than eighty film and television projects over his forty-five-year career. Allmovie described Waterston as having "earned a devoted following with his quietly charismatic, consistently reliable acting work."

The above description is taken from the Wikipedia article about Sam Waterston, licensed under CC-BY-SA, the full list of authors is on Wikipedia.