As Mary Lincoln's dresser, Keckley prepared her for every public occasion; as her confidante, she shared her anxieties; as her traveling companion, she went to the Gettysburg dedication and toured Richmond after the city fell; and, as her attendant, she cared for her after her son Willie's death and her husband's assassination. When Mary Lincoln left the White House in 1865, Keckley accompanied her to Chicago. After seeing the family settled, she returned to Washington, D.C., where she reopened her dressmaking business.
In the spring of 1867 she began to receive letters from Mary Lincoln, who wrote that she was impoverished and planned to sell her clothes and jewelry to raise money. After she begged Keckley to join her in New York City to help with the sale, Keckley closed her business and went. Newspapers had a field day with the "old clothes scandal," heaping scathing criticism on the president's widow for trying to augment her income in what was considered a vulgar manner. The clothes did not sell, however, and Mary Lincoln returned to Chicago. Keckley stayed in New York City to wind up affairs. She raised money within the black community to aid her former employer, but Mary Lincoln refused it. In 1868 Keckley published her autobiography, Behind the Scenes; or, Thirty Years a Slave, and Four Years in the White House, which she said she wrote to help Mary Lincoln financially as well as to counter what she considered unjust criticisms. Given her loyalty to Mary Lincoln, she must have had a strong motive to violate the code of confidentiality.