Blackwell then established a private practice in a rented room, where her sister Emily, who had also pursued a medical career, soon joined her. Their modest dispensary later became the New York Infirmary and College for Women, operated by and for women. Dr. Blackwell also continued to fight for the admission of women to medical schools. In the 1860s she organized a unit of female field doctors during the Civil War, where Northern forces fought against those of the South over, among other things, slavery and secession.
In 1869 Dr. Blackwell set up practice in London and continued her efforts to open the medical profession to women. Her articles and her autobiography attracted widespread attention. From 1875 to 1907 she was professor of gynecology at the London School of Medicine for Women. She died at her home in Hastings in 1910, leaving behind a legacy that would pave the way for countless generations of female physicians.