Separated as an infant from his slave mother (he never knew his white father), Frederick lived with his grandmother on a Maryland plantation until, at age eight, his owner sent him to Baltimore to live as a house servant with the family of Hugh Auld, whose wife defied state law by teaching the boy to read. Auld, however, declared that learning would make him unfit for slavery, and Frederick was forced to continue his education surreptitiously with the aid of schoolboys in the street. Upon the death of his master, he was returned to the plantation as a field hand at 16. Later, he was hired out in Baltimore as a ship caulker. Frederick tried to escape with three others in 1833, but the plot was discovered before they could get away. Five years later, however, he fled to New York City and then to New Bedford, Massachusetts, where he worked as a labourer for three years, eluding slave hunters by changing his surname to Douglass.

At a Nantucket, Massachusetts, antislavery convention in 1841, Douglass was invited to describe his feelings and experiences under slavery. These extemporaneous remarks were so poignant and naturally eloquent that he was unexpectedly catapulted into a new career as agent for the Massachusetts Anti-Slavery Society. From then on, despite heckling and mockery, insult, and violent personal attack, Douglass never flagged in his devotion to the abolitionist cause.

Douglass returned with funds to purchase his freedom and also to start his own antislavery newspaper, the North Star (later Frederick Douglass's Paper), which he published from 1847 to 1860 in Rochester, New York. The abolition leader William Lloyd Garrison (Garrison, William Lloyd) disagreed with the need for a separate, black-oriented press, and the two men broke over this issue as well as over Douglass's support of political action to supplement moral suasion. Thus, after 1851 Douglass allied himself with the faction of the movement led by James G. Birney (Birney, James Gillespie). He did not countenance violence, however, and specifically counseled against the raid on Harpers Ferry, Virginia (October 1859).

During the Civil War (1861–65) Douglass became a consultant to President Abraham Lincoln (Lincoln, Abraham), advocating that former slaves be armed for the North and that the war be made a direct confrontation against slavery. Throughout Reconstruction (1865–77), he fought for full civil rights for freedmen and vigorously supported the women's rights movement.

After Reconstruction, Douglass served as assistant secretary of the Santo Domingo Commission (1871), and in the District of Columbia he was marshal (1877–81) and recorder of deeds (1881–86); finally, he was appointed U.S. minister and consul general to Haiti (1889–91).