Dr. Mary Edwards Walker was the first woman to be appointed as an assistant surgeon in the U.S. Army, she is also the only woman to date to have received the Medal of Honor, the U.S. government's highest and most prestigious military decoration.

Born in Oswego, New York, on Nov. 26, 1832, Walker graduated from Syracuse Medical College with honors in 1855. She subsequently married Albert Miller, and they started a medical practice in Rome, New York, shortly thereafter.

At the onset of the Civil War, Walker, then 23, traveled to Washington seeking a commission as an Army surgeon or a position as a contract surgeon. Both requests were denied as there was no policy in place for hiring female physicians. She then volunteered as a nurse, but continued to request a commission as an Army surgeon. After three years of persistence, she was hired as a contract surgeon and attached to the 52nd Ohio Infantry.

Walker served at the first Battle of Bull Run and the Battle of Fredericksburg, often near the Union front lines.

Army Maj. Gen. George Thomas and Maj. Gen. William Sherman, general of the Union Army, noted that Walker "...passed frequently beyond our lines far within those of the enemy and, at one time, gained information that led Gen. Sherman to modify his strategic operations as to save himself from a serious reverse and obtain success where defeat before seemed to be inevitable."

Walker's insistence on tending to injured civilians inside Confederate territory led to her being captured as a spy by Confederate forces near Chattanooga, Tennessee, in 1864 after helping a Confederate doctor perform an amputation. She was held in a prison in Richmond, Virginia, for four months and commissioned as an acting U.S. Army assistant surgeon following her release.