Nathaniel Kinsman was born on February 6, 1798, the eldest son of Nathaniel (1775-1808) and Deborah (Webb) Kinsman. He began his career as a shipping merchant by consigning a cargo of fish and palampores (a type of hand-painted and mordant-dyed bed cover) to the schooner Springbird, bound for the West Indies. Before its return, Nathaniel left for Amsterdam as a clerk on the Union. Advancing to supercargo two years later, Nathaniel continued to sail ships for William Gray and Pickering Dodge. By 1830, Nathaniel was part owner of the ship Parachute.

Between 1834 and 1839, Nathaniel remained in Salem. During this time he married Rebecca Chase (1810-1882), the daughter of Quakers Abijiah and Mary (Abbott) Chase. They had three children while in Salem: William, Rebecca Reed and Nathaniel. Their fourth child, Abbott, was born in 1844 while the family was in China. While in Salem, Nathaniel continued to ship cargo on vessels he chartered with other merchants. In 1839, he returned to sailing, mastering the Zenobia, which was owned by Daniel Parker of New York.

After a voyage to Canton, Nathaniel arrived in New York, hoping to make a large profit on the sale of teas. When this venture failed, he accepted an offer of partnership with the firm Wetmore and Company, a New York-based merchant house. Nathaniel left Salem for China in June 1843 with his wife, two children (Rebecca and Nathaniel), niece (Mary Anne Southwick), and servant (John Alley). The family arrived in Macao, China, in October 1843. Once the family was settled, Nathaniel left for Canton, to establish a new house for the firm. His wife remained in Macao, serving as a secretary and as the official business hostess for Wetmore and Company. The Kinsmans lived in China for three and a half years.

A month before their planned departure for Salem, Nathaniel succumbed to a reoccurring stomach disorder and died in Macao on April 30, 1847. Rebecca returned to Salem in June 1847 with their two sons (Rebecca Reed had died in 1846), and John Alley. In 1865, Rebecca married Joseph Grinnell of New Bedford.