Sister Deirdre Byrne is a retired colonel in the United States Army Medical Corps, who has served the country for 29 years as an army and missionary surgeon, performing emergency surgeries after crises in Kenya, Afghanistan, Haiti, Iraq, and Sudan. She currently serves as a missionary sister and superior of her community, the Little Workers of the Sacred Hearts, in her hometown of Washington, D.C. She is double board-certified in family medicine and general surgery. Her apostolate performs overseas medical missionary surgery and provides free medical care for the poor and uninsured.