He was born in 1797 to Nicholas Brown, Jr., the namesake patron of Brown University. Collecting American books in the mid-19th century, John Carter Brown amassed thousands of early American volumes. He was the first American to join the Hakluyt Society as a charter member in 1846. He fathered a son at age 64, John Nicholas Brown I (1861–1900) continued his father's collection and in his testament assigned funds for the library building. John Carter Brown died in 1874.
^"History of the John Carter Brown library". Retrieved 2011-04-21. "Although the Brown family had been acquiring books since early in the eighteenth century, the present collection was not fully launched until the mid-nineteenth century when John Carter Brown (1797–1874) began avid pursuit of Americana, an area of interest he termed “the Great Subject.” His son, John Nicholas Brown (1861–1900), actively continued this tradition and before his untimely death had conceived the idea of giving the Library to the world of historical research as a memorial to his father."