Florence Aby Blanchfield was born in Shepherdstown, West Virginia, the fourth of eight children of Mary Louvenia (née Anderson), a nurse, and Joseph Plunkett Blanchfield, a mason and stonecutter. She grew up in Oranda, Virginia, attending public school until 1898, when she attended the private Oranda Institute. In addition to having a mother who was a nurse, Blanchfield's two sisters also became nurses, and her maternal grandfather and an uncle were physicians.[5]
During World War I, she enlisted in the US Army Nurse Corps (ANC), and served as acting chief nurse, in Angers, and Coëtquidan, France, from August 1917 to January 1919. She was assigned to many military hospitals. She returned to civilian life for a period after the end of the War, but was drawn back to active service.
In 1935, she was assigned to Washington D.C. to the office of the superintendent, for personnel matters in the corps. She became assistant superintendent in 1939, acting superintendent in 1942, and served as superintendent from 1 June 1943 until September 1947.
She was instrumental in gaining full rank for nurses, by the Army and Navy Nurse Corps Law of April 16, 1947.[7] This was preceded by temporary full commissioned status granted in 1944. During World War II, she also saw the rapid growth of the ANC from several hundred members to more than 50,000.[5] In 1947 she became the first woman to receive a military commission in the regular army.[3][4]
For her accomplishments on behalf of the ANC, she was awarded the Distinguished Service Medal in 1945. Blanchfield was also awarded the Florence Nightingale Medal by the International Red Cross (1951) and West Virginia's Distinguished Service Medal (1963).[5]