This is a Sans Arcs chief and not the Miniconjou nephew of Sitting Bull.

Stanley J. Morrow photographed him and his family sometime in the 1870s. In the Morrow collection of the W.H. Over Museum are two views of White Bull wearing the same shirt ( I just discovered this is in the NMAI collection and on display now at the Eilteljorg Museum, misidentified as "Mandan") and leggings, but holding a pipe and tobacco bag instead of an eagle tail fan. He also has feather war honor hair ornaments that are lacking in the DPL photo. Hard to see, but he may also have the quirt hanging from his wrist in all the photos.
— Bob Brewer / buffaloman