Manley is a physician and health care administrator who has worked in the public health field since 1976. A native of Jackson, Mississippi, she graduated cum laude from Spelman College and earned her MD from Meharry Medical College. She completed her residency in pediatrics at Cook County Children's Hospital in Chicago, and, in 1962 became the first African American womanand the youngest person ever to be named Chief Resident of that hospital's 500 bed facility. She holds a Master of Public Health degree from the John Hopkins University School of Public Health and Hygiene.