The depiction of Indians on currency dates back to the Indian medals the
government would give to cooperative chiefs, which would show the face of
the chief on one side.  The first Indian cent appeared in 1859, breaking
with the tradition of depicting Lad y Liberty on the front.  The five-cent
piece was introduced in 1866, but the buffalo nickel, with and Indian's
face on the reverse, was not minted until 1913.  Shown here is Two Guns
White Calf, a Blackfoot chief, who was chosen as a model for the coin. 
Unfortunately, it had to be discontinued a few years later, owing the
difficulty of clearly striking the ornate design.