During the Civil War, after Union forces gained control of the Sea Islands off the coast of South Carolina, owners abandoned their plantations and the people who lived there. In response, the federal government launched a new effort to provide education for formerly enslaved African Americans. In 1862, Forten traveled to St. Helena Island where she worked for two years as one of the program’s first teachers. It was here that she met Harriet Tubman in 1863 and befriended Robert Gould Shaw, the commander of the all-black 54th Massachusetts Infantry. Forten wrote of her experiences in 1864 issues of the Atlantic Monthly.
Following repeated bouts of pneumonia and the death of her friend, Shaw, Forten returned to New England in 1864. In addition to teaching, over the years Forten served as a nurse, song leader, and companion for the elderly. She became a clerk in the U.S. Treasury Department 1873, and then in 1878 she married the Reverend Francis J. Grimké, a former slave and minister of DC’s Fifteenth Street Presbyterian Church. In 1896, Forten Grimké went on to help found the National Association of Colored Women, and throughout the 1890s published poems about her life in Washington DC. She continued to call the city home until she passed away in 1914.