Thalia Dondero was born January 23, 1921 in Greeley, Colorado. She lived in Colorado and Wyoming before her family settled in Bakersfield, California. Dondero moved to Las Vegas in 1943 when her employer took a job with Basic Magnesium, Inc., and asked that she follow him. She married Harvey Dondero, who taught English and journalism for local high schools, in 1946.
Dondero was the first woman elected to the Clark County Commission. She ran her first successful campaign in 1974 and held office for twenty years. While on the commission, she helped create Red Rock Canyon and Valley of Fire state parks, to modernize McCarran International Airport and University Medical Center, and served on the Water Authority Board. Dondero served as a member of the Board of Regents for the Nevada System of Higher Education for twelve years.