Theodore Dwight Weld (November 23, 1803 – February 3, 1895) was one of the architects of the American abolitionist movement during its formative years from 1830 to 1844, playing a role as writer, editor, speaker, and organizer.

Harriet Beecher Stowe partly based Uncle Tom’s Cabin on Weld's text; the latter is regarded as second only to the former in its influence on the antislavery movement.

Weld remained dedicated to the abolitionist movement until slavery was ended by the Thirteenth Amendment to the United States Constitution in 1865.

He shunned the cities, and chose to labor in the country districts, where newspapers were few, and his activities were seldom reported except by abolition journals.

[6] At age 14 Weld took over his father's hundred-acre (forty-hectare) farm near Hartford, Connecticut, to earn money to study at Phillips Academy in Andover, Massachusetts, attending from 1820 to 1822, when failing eyesight caused him to leave.

[9]: 31  The famous evangelist Charles Grandison Finney was based in Oneida County, and according to him, Weld "held a very prominent place among the students of Hamilton College, and had a very great influence.

[4]: 16 Later in 1827, abandoning Hamilton on Stuart's recommendation, he enrolled in the new Oneida Institute of Science and Industry in nearby Whitesboro, New York, the most abolitionist school in the country, his fees paid for him by Stuart,[13]: 56  after first participating in a pilot program, staying at the farmhouse of founder George Washington Gale in Western, New York, working in exchange for instruction.

While at the Oneida Institute, where he was in charge of the cow-milking operation,[9]: 63  he would spend two weeks at a time traveling about, lecturing on the virtues of manual labor, temperance, and moral reform.

I state the impression which I had of him as a boy, and it may seem extravagant, but I have seen crowds of bearded men held spell-bound by his power for hours together, and for twenty evenings in succession.

Since he was "a living, breathing, and eloquently-speaking exhibit of the results of manual-labor-with-study,"[19]: 42  the brothers then created, so as to employ Weld, the Society for Promoting Manual Labor in Literary Institutions [non-religious schools], which promptly hired him as its "general agent" and sent him on a factfinding and speaking tour.

[20]: vi [15][4]: 3–5 Weld had also been commissioned to find a site for a great national manual labor institution where training for the western ministry could be provided for poor but earnest young men who had dedicated their lives to the home missionary cause in the "vast valley of the Mississippi."

[19]: 43 During his year as a manual labor agent, Weld scouted land, found the location for, and recruited the faculty for the Lane Seminary, in Cincinnati.

He first worked, in 1833, at convincing the other students at Lane that immediatism, ending slavery completely and immediately, was the only solution and what God wanted.

Weld declined an appointment at Oberlin as professor of theology, saying abolitionism was a higher priority;[9]: 123  he directed Shipperd to Charles Finney.

Weld became one of the leaders of the antislavery movement, working with the Tappan brothers, New York philanthropists James G. Birney and Gamaliel Bailey, and the Grimké sisters.

"Public awareness of abolition [in New York State] reached its peak with the activities of Theodore Weld from February to early July, 1836.

"[13]: 151 In 1836, Weld discontinued lecturing when he lost his voice, and was appointed editor of its books and pamphlets by the American Anti-Slavery Society.

[23] Among the books he edited was James Thome and J. Horace Kimball's Emancipation in the West Indies : a six months' tour in Antigua, Barbadoes, and Jamaica, in the year 1837.

Their first home as newlyweds was in Fort Lee, New Jersey, where he, his wife, and her sister researched and co-wrote the very influential 1839 book American Slavery as It Is: Testimony of a Thousand Witnesses.

[citation needed] In early 1853, Weld was offered the position of Director of a school of the Raritan Bay Union at Eagleswood in Perth Amboy, New Jersey.

Here, Weld had "charge of Conversation, Composition, and English Literature",[27][full citation needed] and Angelina taught history.

His brother Ezra Greenleaf Weld, a famous daguerreotype photographer, was also involved with the abolitionist movement (see Fugitive Slave Convention).