When he was a boy, Henry Highland Garnet's family escaped from slavery in Maryland and settled in New York. He attended the African Free School with James McCune Smith, and subsequently studied for the Presbyterian ministry. At the 1843 black national convention in Buffalo, he declared that American slaves who would be free "themselves must strike the first blow!" Many delegates feared this call for a slave insurrection and Garnet's motion was narrowly defeated.

Over the next 20 years, Garnet led efforts in Britain and America to boycott slave-made goods. As pastor of New York's Shiloh Church after 1855, Garnet embraced black emigration to Africa, provoking a split with McCune Smith. Garnet spent the war shepherding a Washington congregation, and on February 12, 1865, he became the first black person to deliver a speech to the U.S. House of Representatives. The speech was published as A Memorial Discourse, with an introduction by James McCune Smith. Garnet returned to Shiloh in the 1870s. He served as U.S. Minister to Liberia in 1881, and died there the next year.