Cox enlisted in October 1862, in Knox County, Illinois. She served with her husband in the 83rd Illinois Infantry Nurse Corps throughout her career as a Civil War Nurse, serving at Fort Henry, Fort Donelson, and Clarksville. Because Cox remained with the same regiment, and spent much of her time with them at Fort Donelson, her experiences weren't as varied as the stories of some Civil War nurses. Civil War nurses did much more than change bandages, tend wounds, and dispense medicine. They also passed out supplies, wrote letters for soldiers and read to them, cooked and served meals, and did laundry.