Michael Spears was born in Chamberlain, South Dakota near the Lower Brulé Indian Reservation to Sičangu Lakota parents and lived there until he was in fifth grade.

[4] Spears' debut role as the child character Otter, in the Academy-Award-winning 1990 film Dances with Wolves, earned him national notice at thirteen years old.

Spears' film credits include a major role as the character Dog Star in the 2005 Steven Spielberg-produced mini-series, Into the West, which aired on TNT.

[7] In 2005, Michael and Eddie Spears modeled for Cochiti Pueblo fashion designer Virgil Ortiz for his "Indigene" clothing line and were featured on the cover of the August 2005 issue of New Mexico Magazine.

Spears often travels to deliver speeches on inspirational and educational topics, including sustainable energy and mental health, and mentors Indigenous youth in Montana and South Dakota.