John Nicholas Brown was born on December 17, 1861 to John Carter Brown II (1797–1874) and Sophia Augusta Brown (1825–1909).[2][3] His father was a collector of American books in the mid-19th century and was the first American to join the Hakluyt Society as a charter member in 1846, and in 1855, he was elected a member of the American Antiquarian Society.[4] His brother was Harold Brown (1863–1900) and his sister was Sophia Augusta Brown (1867–1947), who married William Watts Sherman (1842–1912).[5]