Based on the Steve Martin movie of the same name and featuring a score by Alan Menken, the musical is scheduled to begin performances at Manhattan's Center Theatre Group/Ahmanson Theatre in September.
Esparza is to play the Rev. Jonas Nightengale, the consummate flim-flam man, while Shields has been cast as Marva, the beautiful small-town woman and single mother who challenges everything Jonas believes in, the producers said in a news release.
Rob Ashford is the show's director and choreographer.
"Leap of Faith" is to be presented Sept. 11 through Oct. 24, with the opening scheduled for Oct. 3.
Esparza's Broadway credits include "Speed the Plow," "The Homecoming" and "Taboo."
Shields has starred in Broadway productions of "Cabaret," "Grease," "Chicago," "Love Letters," "The Vagina Monologues" and "Love, Loss and What I Wore."