William Sadler is an American actor best known for his role as Sheriff Jim Valenti in the television sci-fi series Roswell, appearing in 53 episodes from 1999-2002.
He also had a leading role in the short-lived series Wonderfalls, in 2004.
He is also known for his roles in the 1990 action film Die Hard 2 (as Colonel Stuart), as Heywood in the 1994 prison drama The Shawshank Redemption, as the Grim Reaper in the 1991 comedy Bill & Ted's Bogus Journey, and as Kenneth Braun - a man able to achieve a climax in 10 seconds - in Kinsey (2004).
Sadler has made numerous television guest appearances, in shows such as Newhart; St. Elsewhere; Roseanne; Murphy Brown; The Outer Limits; Star Trek: Deep Space Nine; Ed; Law & Order: Criminal Intent; JAG; Third Watch; Law & Order: Trial by Jury; Law & Order; CSI: Crime Scene Investigation; NUMB3RS; and The Black Donnellys.
Other films he has appeared in include Project X (1987), K-9 (1989), Rush (1991), Bordello of Blood (1996), Disturbing Behavior (1998), The Green Mile (1999), Purple Heart (2005), Devour (2005), Unspoken (2006), and A New Wave (2007).
He also appeared in the 2006 television mini-series The Path To 9/11, about the events leading up to the US terrorist attacks on September 11, 2001.