He was born in Bethel, Connecticut, on the 5th of July 1810, his father being an inn and store-keeper. Barnum first started as a store-keeper, and was also concerned in the lottery mania then prevailing in the United States. After failing in business, he started in 1829 a weekly paper, The Herald of Freedom, in Danbury; after several libel suits and a prosecution which resulted in imprisonment, he moved to New York City in 1834, and in 1835 began his career as a showman, with his purchase and exploitation of a coloured woman, Joyce Heth, reputed to have been the nurse of George Washington, and to be over a hundred and sixty years old.
With this woman and a small company he made well-advertised and successful tours in America till 1839, though Joyce Heth died in 1836, when her age was proved to be not more than seventy. After a period of failure, he purchased Scudder's American Museum, New York, in 1841; to this he added considerably, and it became one of the most popular shows in the United States. He made a special hit by the exhibition, in 1842, of Charles Stratton, the celebrated “General Tom Thumb”. In 1844 Barnum toured with the dwarf in England. A remarkable instance of his enterprise was the engagement of Jenny Lind to sing in America at $1,000 a night for one hundred and fifty nights, all expenses being paid by the entrepreneur. The tour began in 1850.
Barnum retired from the show business in 1855, but had to settle with his creditors in 1857, and began his old career again as showman and museum proprietor. In Brooklyn, New York in 1871, he established the "Greatest Show on Earth," a travelling amalgamation of circus, menagerie and museum of "freaks," &c. In 1881 he merged with James Bailey to create the Barnum & Bailey Circus, which toured around the world. The show's primary attraction was Jumbo, an African elephant he purchased from the London Zoo.
He died on April 7, 1891, and his circus was sold to Ringling Brothers in 1909 (or 1907?).
Barnum wrote several books, including The Humbugs of the World (1865), Struggles and Triumphs (1869), and his Autobiography (first in 1854, and later editions including 1869).