Gil Grissom

Gilbert Arthur Grissom (born August 17, 1956), Ph.D. is a fictional character portrayed by William Petersen on the CBS crime drama CSI: Crime Scene Investigation and its sequel, CSI: Vegas. Grissom is a forensic entomologist and for the series' first nine seasons, a CSI Level III Supervisor employed by the Las Vegas Police Department. He appeared in 193 episodes of the original series, where he was succeeded by Raymond Langston (Laurence Fishburne) and later D.B. Russell (Ted Danson). Grissom returned in the sequel series, CSI: Vegas, in 2021.