Though born in Danville, Lady Astor's childhood was spent in nearby Richmond, Virginia. Her family, having become impoverished during the Civil War, had recovered its wealth by her teenage years. Lady Astor subsequently married into more wealth; however, the marriage was short-lived and ended after ten years.

On a journey to England in 1906, Lady Astor met and married her second husband, Waldorf Astor, a descendant of America's first millionaire family. Waldorf Astor was elected to Parliament in 1910 and, following his father's death in 1919, became Viscount Astor. His elevation to the House of Lords, gave Lady Astor the opportunity to run for the seat left vacant by him in the House of Lords. In doing so, Lady Astor won by a substantial majority and became the first female member of the Parliament in Britain. She was also the first woman to introduce a bill into Parliament. The bill aimed to prohibit the sale of alcohol in bars to persons under the age of eighteen. As a member of the conservative Tory party, many of the issues and causes taken up by Lady Astor focused on women and children. On the subject of women's rights she once said, "We are not asking for superiority for we have always had that; all we ask is equality." Lady Astor remained in Parliament until her retirement in 1945. She died in 1964 at the age of eighty-six.