Kyle was born in the Osage Nation in 1886 and attended Catholic school, eventually converting.

[3][4] By the 1900s, Mollie was wealthy from her Osage headright, but deemed incompetent due to federal laws regulating Native Americans requiring her to have an appointed legal guardian.

[4] Mollie is portrayed by Lily Gladstone in Martin Scorsese's 2023 film Killers of the Flower Moon, which focuses on the murders.

[2][4] In 1931, Mollie successfully sued to end her guardianship and gained control of her family's wealth.

[5] She died on June 16, 1937, and is buried at the Greyhorse Indian Village Cemetery in Osage County.