Zahn Tokiya-ku McClarnon[2] was born in Denver, Colorado, the son of a Hunkpapa Lakota mother and a father of Irish ancestry.

When his father was relocated to Omaha, Nebraska, for work, the family lived in the Joslyn Castle and Dundee neighborhoods.

[4][7] McClarnon got his start in a local production of Jesus Christ Superstar at the Chanticleer Theater in Council Bluffs, Iowa.

[9] From 2012 to 2017, McClarnon portrayed Mathias, the Chief of Indian Tribal Police of the Cheyenne reservation, in Longmire, originally an A&E and later a Netflix television series.

[10] McClarnon portrayed Hanzee Dent in the second season of the TV series Fargo, where his performance received critical acclaim.

[18] In 2021, it was announced that McClarnon would star as Joe Leaphorn in Dark Winds, a psychological thriller television series on AMC.

[19][1] McClarnon's first name is in honor of his maternal great-great-uncle,[citation needed] Frank "Francis" B. Zahn, who was an artist and Lakota elder of Standing Rock Indian Reservation.