The person who was most closely associated with the abolitionist movement was: William Lloyd Garrison
William Lloyd Garrison, (born December 10, 1805, Newburyport, Massachusetts, U.S. and died May 24, 1879, New York, New York),was a prominent American abolitionist, journalist, suffragist, and social reformer. He is best known as the editor of the abolitionist newspaper The Liberator, which he founded with Isaac Knapp in (1831-65) and published in Massachusetts until slavery was abolished by Constitutional amendment after the American Civil War. He was one of the founders of the American Anti-Slavery Society, and promoted "immediate emancipation" of slaves in the United States.