Itzin will play a senator who repeatedly locks horns with modern polygamist Bill Henrickson (Bill Paxton). Campbell will appear as a math teacher.
Itzin received a Tony nomination for The Kentucky Cycle and an Emmy nomination for playing the President on "24." He recently appeared on Broadway as Kenneth Lay in Enron.
Campbell's stage credits include Magnetic North, Of Equal Measure, Great Expectations, tick…tick…BOOM! and Reefer Madness, reprising his performance in that last Off-Broadway production in its Showtime movie version. He has appeared on television in "The Book of Daniel" and "All My Children."
"Big Love" currently stars Bill Paxton, Chloë Sevigny, Jeanne Tripplehorn, Ginnifer Goodwin, Harry Dean Stanton, Željko Ivanek, Amanda Seyfried, Grace Zabriskie, Matt Ross, Mireille Enos and Cassi Thomson.