In April 1862, Susie Baker and many other African Americans fled to St. Simons Island, occupied at the time by Union forces. Within days her educational advantages came to the attention of army officers, who offered to obtain books for her if she would organize a school. She thereby became the first black teacher for freed African American students to work in a freely operating freedmen's school in Georgia. She taught forty children in day school and "a number of adults who came to me nights, all of them so eager to learn to read, to read above anything else." She taught there until October 1862, when the island was evacuated.
While at the school on St. Simons Island, Baker married Edward King, a black noncommissioned officer in the 33rd United States Colored Infantry Regiment. For three years she moved with her husband's and brothers' regiment, serving as nurse and laundress, and teaching many of the black soldiers to read and write during their off-duty hours. In 1866 she and Edward returned to Savannah, where she established a school for the freed children. Edward King died in September 1866, a few months before the birth of their first child. In 1867 she returned to her native Liberty County to establish another school. In 1868 she again relocated to Savannah, where she continued teaching freedmen for another year and supported herself through small tuition charges, never receiving aid from the northern freedmen's aid organizations.
In the 1870s King traveled to Boston as a domestic servant of a wealthy white family. While there she met Russell L. Taylor, also a native of Georgia. She returned home to Liberty County to marry Taylor on April 20, 1879. She remained in Boston for the rest of her life, returning to the South only occasionally. After a trip to Louisiana in the 1890s to care for a dying son, she wrote her Reminiscences, which were privately published in 1902. She died ten years later. She is buried next to her first husband at Mount Hope Cemetery in Roslindale, Massachusetts.