Before she became Gibbs favorite, Pauley could actually be seen in an ABC Afterschool Special "The Magical Make-Over". She later had guest roles on Frasier, The Drew Carey Show, Dawson's Creek, 24, and CSI before landing at NCIS.
Before he was Tony DiNozzo, Michael started out as Theo Huxtable's roommate on The Cosby Show. He then spent time in The City (formerly the ABC soap Loving) and then opposite Jessica Alba in Dark Angel.
Mark Harmon was a star long before he signed up for NCIS. Die hard fans might remember him from the primetime soap Flamingo Road, Dr. Caldwell for St. Elsewhere, or the third wheel in the Dave and Maddie triangle on Moonlighting. However, we're still mourning his untimely death as Agent Simon Donovan, CJ's romantic interest on The West Wing.