Diddock nee La Flesche was born in 1862 on the Omaha Reservation. Her father Joseph La Flesche (1822–1888) was the head chief of the Omaha Tribe. La Flesche Farley's siblings include Susette La Flesche, Susan La Flesche Picotte, and Rosalie La Flesche Farley. Her half brother was Francis La Flesche.
