The Ordained features English actor Charlie Cox (Boardwalk Empire) as Tom Reilly, the son of a Kennedy-esque family who leaves the priesthood and becomes a lawyer to prevent his politician sister from being assassinated.
Neill will portray Michael Thomas Reilly, Tom's father, an ambitious former three-term Governor of New York and one-time presidential candidate.
Garcia will play Carlos, a private investigator who works at Tom's law firm.
Last year Neill and Garcia co-starred in Fox's sci-fi drama Alcatraz which lasted only 13 episodes.
The Ordained cast also includes Emmanuelle Chriqui (Entourage), Audra McDonald (Private Practice), and Nestor Serrano (Bad Boys)
RJ Cutler will direct the script by journalist Lisa Takeuchi Cullen who will executive produce along with Frank Marshall, Larry Shuman and A.B. Fischer.