William Petersen stars as Gil Grissom, Marg Helgenberger as Catherine Willows, and George Eads as Nick Stokes in the long-running US crime drama Csi: Crime Scene Investigation.
Main cast
- Gil GrissomWilliam Petersen1–9, 11 (recurring)Main
- Catherine WillowsMarg Helgenberger1–12Main
- Nick StokesGeorge Eads1–15Main
- Sara SidleJorja Fox2–8, 11–15 (recurring in 9)Main
- Warrick BrownGary Dourdan1–9Main
- Jim BrassPaul Guilfoyle1–14Main
- Greg SandersEric Szmanda3–15Main
- Al RobbinsRobert David Hall2–15 (recurring in 1)Main
- David HodgesWallace Langham5–15 (recurring in 3–4)Main
- Raymond LangstonLaurence Fishburne9–11Main
Supporting cast
- D.B. RussellTed Danson12–15Supp
- Morgan BrodyElisabeth Harnois12–15Supp
- Julie FinlayElisabeth Shue12–15Supp
- Wendy SimmsLiz Vassey6–9 (recurring in 5)Supp
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About this cast
CSI: Crime Scene Investigation follows a team of Las Vegas forensic investigators as they solve crimes using scientific evidence. The main cast includes William Petersen, Marg Helgenberger, and George Eads as the three lead crime-scene experts.
FAQs
Who plays Gil Grissom in CSI?
Gil Grissom is played by William Petersen. He was the main character for the first nine seasons and returned for guest appearances in season 11.
Who plays Catherine Willows in CSI?
Catherine Willows is played by Marg Helgenberger. She appeared as a main cast member from season 1 through season 12.
Why did William Petersen leave CSI?
William Petersen left the main cast after season 9 to pursue other acting and producing opportunities, though he returned for a few guest episodes later.
Did CSI have any spin-offs?
Yes. CSI: Miami (2002–2012) and CSI: NY (2004–2013) were both successful spin-offs set in different cities.
Sources & where to watch: IMDb · Wikipedia · Where to watch (JustWatch UK) · Updated June 2026