Contrary to popular belief, Geronimo was not a chief--as he is portrayed in this film--and was never even a war chief (during times of war Apaches often appointed a more experienced warrior to be war chief; when the war ended, leadership reverted back to the "regular" chief). Geronimo was a medicine man and someone to whom the actual chiefs came for advice. He led raids, but any Apache who was able to find warriors to follow him could lead raids. Many whites thought he was a chief because in negotiations he often acted as spokesman for Juh, the real chief, but Geronimo himself had no authority to conduct negotiations or speak for the tribe. The reason he spoke for Juh, however, was that Juh had a speech impediment and didn't want the whites to know it. In any case he knew that Geronimo was a more forceful and effective speaker than he was, so he let Geronimo do the talking, but it was Juh who made all the decisions.
Miguel Inclan also portrayed Geronimo in the 1948 John Ford film "Fort Apache."