In 1941 he was hired by the Bureau of Indian Affairs to design and establish the Museum of the Plains Indian in Browning, Montana, duties which he combined with his own extensive field work on the art, culture, and history of the Blackfeet Tribe.
Leforge joined the Montana militia in 1867 in the Bozeman, Montana and Livingston, Montana areas, acquiring both military experience and acquaintance with native Americans tribes and ways (including raiding parties by Piegan Blackfeet, his father working near Fort Ellis, Montana.