She went to Baylor College for Women and studied journalism. After their wedding, she and her husband moved away from Texas to work at the University of North Carolina at Chapel Hill. There she was offered a position as associate professor and earned her PhD in history.[3]
Not many women were active historians at the time. When Johnson was first mentioned in the American Historical Review she was referred to as "he". She published several studies of the Antebellum South, delving into race relations, religion, freed slaves, women's life and other aspects that had previously been treated lightly.[4] Her award-winning book Ante-Bellum North Carolina: A Social History is still considered an important resource.[2][5]
She became involved in women's organizations and issues after the end World War II, when opportunities for women became limited.[6] She and her husband collaborated on several research projects.[7]