Who played the original lead character Gil Grissom?

William Petersen played the original lead character Gil Grissom. Petersen portrayed Grissom in CSI: Crime Scene Investigation from the show’s 2000 premiere and served as its principal star for much of the original run.

Grissom was a forensic entomologist and CSI supervisor whose scientific approach made him different from the conventional television detective. His expertise in insects, biology and trace evidence became a defining part of the character, while Petersen’s restrained performance established the tone of the series.

Petersen was a regular cast member through the first eight seasons and the beginning of season nine. After leaving the main cast, he returned for selected guest appearances, including the feature-length finale, “Immortality,” in 2015. He also reprised Grissom in the sequel series CSI: Vegas.

The character is sometimes confused with later CSI leads. Laurence Fishburne and Ted Danson eventually took leading roles in the original series, but neither played Grissom; Danson portrayed D.B. Russell, while Petersen remained the actor associated with the first lead investigator.