The women’s rights activist who organized the Seneca Falls Convention in 1848 was Elizabeth Cady Stanton. She played a crucial role in advocating for women's suffrage and gender equality. The convention produced the Declaration of Sentiments, which outlined the grievances and demands of women, including the right to vote. This pivotal event marked the beginning of the organized women's rights movement in the United States, influencing future activism and leading to significant social change.