Born and raised in South Carolina, Dr. Walker lived on Redcliffe Plantation caring for animals and accompanying her mother on visits to help sick neighbors. Dr. Walker's mother inspired her to study medicine at an early age; she remembered friends calling her "Doc" by the age of thirteen, a name that stayed with her throughout her lifetime. At a time when few women attended college, Dr. Walker graduated from Goucher College in Baltimore, Maryland and continued her doctoral education at the Medical College of Georgia, the only female graduate in 1927. She completed her internship at the Railroad Hospital in Savannah, Georgia and then moved onto The Johns Hopkins University in Baltimore, Maryland to do medical research.

At the onset of the Depression in 1929, Dr. Walker responded to a request for a medical doctor in the small town of Friendship. The disproving townsfolk never expected a twenty-five year old female doctor, but they quickly learned that she was committed to her profession after witnessing the full recovery of her first patient, a dog hit by a car. Dr. Walker married John Fletcher Wilson in 1932 and moved her medical office to their family farm in Lothian, where she treated locals for one dollar and delivered babies at home for fifteen dollars. The community particularly admired Dr. Walker for her egalitarian practices; she did not segregate her patients nor did she refuse anyone treatment based on their location or ability to pay. Dr. Walker often served people accessible only by horseback, and when patients could not pay, she took payments in commodities offered by the family. She remembered taking care of more than six generations in a single family.

Dr. Walker achieved many extraordinary medical accomplishments that widely benefited her community. She became the Chief of Staff at Anne Arundel Hospital (now Anne Arundel Medical Center) in 1951, an institution that initially denied her staff admission earlier in her career. She also served as president of the Anne Arundel Medical Society. She diagnosed the first case of Rocky Mountain fever in Maryland in the 1940's and helped establish syphilis and prenatal clinics in the county. Dr. Walker ignored the Jim Crowism of the era and helped many African American women deliver their babies at home or at The Johns Hopkins University Hospital when their local hospital, in Annapolis, denied them use of the main facility.