Joseph, also called "Insta Maza" (Iron Eye), had started with the American Fur Company at age 16, after accompanying his father from the age of 10 on his trips. After his parents separated because of his father's long trips, the younger La Flesche lived with his mother and her family among the Omaha. She married again, as did his father. Joseph's half-brother, Frank LaFlesche (White Swan) became a chief of the Ponca and was influential in the lives of Joseph's children.