Carl Roessel Slater won a special election for a seat representing five Navajo communities in the Arizona portion of the reservation. He took office Thursday.
Slater had served as a spokesman for the tribe's legislative branch before stepping down to run for the council seat. He beat out four others to replace longtime lawmaker Nelson BeGaye, who retired for health reasons.
Slater is the grandson of the late Ruth and Robert Roessel of Round Rock, Arizona, who helped found the nation's first tribal college on the Navajo Nation.
The 24-member Tribal Council meets next week in the tribal capital of Window Rock for the start of its weeklong fall session.