Bloomfield was incorporated as a township from portions of Newark Township by an Act of the New Jersey Legislature on March 23, 1812. The new township took its name from the Presbyterian parish, which had been named for Governor of New Jersey, Joseph Bloomfield.

At that time it covered 20.52 square miles (now 5.4 square miles) and included several villages which left Bloomfield during the century.

Their names and dates of separation were Belleville (April 8, 1839), Montclair (April 15, 1868), Woodside (March 24, 1869) and Glen Ridge (February 13, 1895).

Bloomfield was incorporated as a town on February 26, 1900. In July 1981, residents voted to revert the designation to Township.