US former actor Nathan Chasing Horse has been sentenced to least 37 years in prison for sexually assaulting Indigenous women and girls.

The 49-year-old, known for his role in Dances With Wolves, had earlier been convicted of 13 charges, mostly relating to the assault of three women. One victim was 14 when the abuse began.

Chasing Horse, who is also known as Nathan Lee Chasing His Horse, had a reputation as a medicine man among Indigenous tribes across the US and Canada.

Accusers and their families told the Nevada court he exploited his position as a spiritual leader, with multiple victims attending his ceremonies or approaching him for medical help.

One of his victims, Corena Leone-LaCroix, who was 14 at the time the abuse started and came forward publicly, said: "There is no way to get back the youth, the childhood loss, my first time, my first kiss, the graduation I never got to have."