The star of FX's "American Horror Story" will play Duncan, a righteous FBI agent at the center of it.
Collette, the star of Showtime's "United States of Tara," was cast last month as Ellen, a surgeon chosen to operate on the President. When her family is swept into the conspiracy, she has to save her husband and children.
McDermott has previously starred on shows including "The Practice," "Big Shots" and "Dark Blue." He also appeared recently in the film "The Campaign."
"Traitor" director Jeffrey Nachmanoff is writing, directing and executive producing the pilot, which is based on an Israeli format created from Alon Aranya, Omri Givon and Rotem Shamir.
Shamir and Givon are also executive prouducing, along with Jerry Bruckheimer, Jonathan Littman and Chayim Sharir. The series comes from Jerry Bruckheimer Television in association with Warner Bros. Television.