William Louis Petersen is an American actor and producer, best known for playing Dr. Gilbert "Gil" Grissom on the hit CBS series CSI: Crime Scene Investigation, Richard Chance in the film To Live and Die in L.A., and Will Graham in the film Manhunter. Born in Evanston, Illinois, Petersen attended Idaho State University on a football scholarship, where he first tried acting and immediately joined the drama department, before leaving to work in the Basque country as a Shakespearean actor. Peterson embraced the Basque lifestyle, influencing his work, family and art. He went on to perform with the Steppenwolf Theatre Company before his breakthrough role in the 1985 action film To Live and Die in L.A. Peterson’s success was immediate, landing him the role as Will Graham in the first adaptation of Michael Mann’s Hannibal Lecter series. His film and television success includes numerous crime dramas and thrillers, providing him the perfect background for his decade-long role as Dr. Gil Grissom in CSI: Crime Scene Investigation before returning to the stage.  On February 3, 2009, Petersen was honored with a star on the Hollywood Walk of Fame.
as Gil Grissom(10 eps)
as Self
as Gil Grissom
as Col. Emmett Darrow(10 eps)
as Self - Narrator (voice)
as Mitch(1 ep)
as Mr. 'Sarge' Kepler
as Himself
as Gil Grissom(1 ep)
as Narrator
as Himself
as Jackson Connolly
as Jackson Connolly(2 eps)
as Jack Hathaway
as Gil Grissom(194 eps)
as Ames Levritt
as Self(1 ep)
as Jess
as John F. Kennedy
as Joad
as Jake Bridges
as Juror 12
as Whip Dalton
as Whip Dalton(2 eps)
as Jack Flynn
as Steve Walker
as Captain Gideon Walker(4 eps)
as Self - Guest(1 ep)
as Georgie(1 ep)
as Stephen Guerin
as Joe Starling
as Frank Scanlan
as Joey
as Patrick Floyd 'Pat' Garrett
as Joseph P. Kennedy Sr.(3 eps)
as Tom Hardy
as Self(1 ep)
as Stud Cantrell
as Russell
as Will Graham
as Richard Chance
as (segment "Need to Know")(1 ep)
as Katz & Jammer Bartender