American Horse was first known as Manishnee (Cannot Walk, or Played Out) and his nickname was Spider. When he was born, his old grandfather said: 'Put him out in the sun! Let him ask his great-grandfather, the Sun, for the warm blood of a warrior!' And he had warm blood." His father Sitting-Bear, the leader of the True Oglalas, was killed in battle while he was still very young and he was raised by an uncle. As a youth, American Horse participated in war parties against the Crow and Shoshones.