George Palmer Putnam, who went on to found a New York publishing dynasty, received his first job from Leavitt.
Although most accounts give the name of Leavitt's wife as Joan Ayres – and Ayres was subsequently the middle name of Leavitt's son George, who took over his father's publishing business – Sidney Perley, in his authoritative The Essex Antiquarian, lists under the 'Adams Genealogy' the information that Major John Adams of Andover, Massachusetts, had daughters Louisa (who married 'Jonathan Leavitt') and Hannah (who married "Daniel Appleton of Haverhill' of "the Appleton Publishing House of New York City.").
The store on Exchange Place was divided into two sections, with Appleton's son William later taking charge of the bookselling functions.
[6] Appleton and his son subsequently moved their business to what was known as Clinton Hall, on Beekman Street, where they established themselves as well-known booksellers.
[6] With his partnership with Appleton dissolved, Leavitt became the leading publisher of religious and theological works in New York city.
"[10] In 1833, Leavitt publish Putnam's first book: Chronology, or An Introduction and Index to Universal History, Biography, and Useful Knowledge.
[9] Broadway emerged early as center of the publishers who came to New York City, and Leavitt was among the pioneers of the business.
In 1841, for instance, its presses turned out Merciful Rebukes: A Sermon Preached in the Rutgers Street Church, New York, on Friday, May 14, 1841, On Occasion of the National Fast Recommended by the President of the United States.
[18] The pair were soon joined in the business by George Ayres Leavitt, Jonathan's son, who had recently graduated from Phillips Academy in Andover, and who had served an early apprenticeship with publishers Robinson & Franklin.