In April 1862, she and other enslaved people fled to St. Simon's Island, then occupied by Union forces. Recognizing her abilities, Union officers asked her to set up a school, which she did (both children and adults attended). There, she married Edward King, a black officer. She followed her husband's regiment as it traveled; she eventually became a volunteer nurse — the first African woman to do so during the Civil War.
Widowed during the Civil War, Susie moved north to Boston in the 1870s, and there married Russell Taylor. She remained in Boston for the rest of her life. She published her book Reminiscences of My Life in Camp with the 33d United States Colored Troops in 1902 (she dedicated it to Col. Thomas Wentworth Higginson, who had led that regiment). From that book:
I taught a great many of the comrades in Company E to read and write, when they were off duty. Nearly all were anxious to learn. My husband taught some also when it was convenient for him. I was very happy to know my efforts were successful in camp, and also felt grateful for the appreciation of my services. I gave my services willingly for four years and three months without receiving a dollar. I was glad, however, to be allowed to go with the regiment, to care for the sick and afflicted comrades.
And, she concludes:
We are similar to the children of Israel, who, after many weary years in bondage, were led into that land of promise, there to thrive and be forever free from persecution; and I don't despair, for the Book which is our guide through life declares, "Ethiopia shall stretch forth her hand."
What a wonderful revolution! In 1861 the Southern papers were full of advertisements for "slaves," but now, despite all the hindrances and "race problems," my people are striving to attain the full standard of all other races born free in the sight of God, and in a number of instances have succeeded. Justice we ask, — to be citizens of these United States, where so many of our people have shed their blood with their white comrades, that the stars and stripes should never be polluted.