Belleville's early history involves two revolutions: the American and the Industrial. Originally settled in Colonial times, Belleville, then known as Second River, was the place where Josiah Hornblower built the first steam engine to be manufactured in America. Hornblower is one of 66 Revolutionary War veterans buried in the township, which was also the site of a significant battle during the War of Independence. Many structures built in the township's early years, such as the Dutch Reformed Church, still stand today.

The township's borders were redrawn a number of times in the decades after Belleville was officially incorporated in 1839. Neighboring Nutley, for instance, was carved out of a section of the township in 1874, and the two communities share a friendly rivalry to this day.  

Today, the township is known for its prominent former residents, a list that includes some of America's most famous musicians and writers. Every spring, Belleville, "The Cherry Blossom Capital of America," hosts visitors from around the globe who converge on Branch Brook Park to see the township's signature trees in bloom.

Belleville's municipal government is defined under state law as council-manager, with a seven-member elected township council and an appointed township manager who oversees all municipal departments such as police, fire and public works. Like communities elsewhere in New Jersey with the same form of government, Belleville's regular council elections are held in May and candidates do not run as members of political parties.