The Passion of The Christ star Caviezel will portray Ward Allen in the film, Savannah, and Ejiofor his sidekick Christmas Moultrie.
Director Annette Haywood-Carter's historical film will also feature Bradley Whitford, Jack McBrayer and Hal Holbrook.
Haywood-Carter tells WENN, "Ward Allen was a romantic naturalist, an aristocrat who turned his back on a life of material comfort to become a market hunter.
"He and Christmas Moultrie became business partners, confidantes and life-long friends and together they tried to navigate the vicissitudes of social, industrial, environmental and personal change that threatened their way of life.
"This is an amazing cast, beyond my wildest imagination."