She is first mentioned when she accompanied her husband-brother Sayri Túpac from Vilcabamba to Spanish controlled territory in 1556.
Cusi Huarcay was forced to instigate a legal court process to get her allowance.
She fulfilled her informal role to receive subjects from Vilcabamba, and described as frugal but in debt.
In 1564, Cusi Huarcay was housed by Arias Maldonado, and was able to have her daughter Beatriz released from the convent.
This caused governor Lope García de Castro to have Maldonados exiled to Spain, and Beatriz returned to the convent.