Established in 1846 as Newton City and in 1847 the name was changed to Newton. Ten years later Newton was incorporated. It is commonly held that Newton was named after a Sergeant Newton, a member of General Marion's Army and a close friend of Sergeant Jasper. During the American Revolution, the two were often together in deeds of daring such as those which made each man in Marion's band a hero.

A dissenting view is held by a Newton family residing in California, who contend their grandfather founded Newton. Their claim is that Joseph Kaiser Newton migrated to the area from West Virginia. In May of 1846, Thomas Anderson located the county seat of Jasper County, Iowa. He set up a pole on the present site of Newton. On August 17, 1846, the sale of lots began. The highest price was $37.00 and the cheapest was $5.00. Twenty-nine blocks of eight lots each were placed up for sale.

The Newton Library Association was organized in 1859 and numbered 132 volumes. Hazel Dell Academy, a private school, was organized in 1856 and operated for a number of years. Taxes were levied to pay for county services, four mills, for the school's one-half mill. The first independent school district was established in the spring of 1863. On May 25, 1864, the school board contracted for two schoolhouses to be built at a huge cost of $1,480. During 1856 and 1857 converts to the Mormon religion streamed through Newton on their trek westward. Churches were an important part of Newton's early development and these churches were organized in the following years: Methodist Church in 1848, Baptist Church in 1852, Presbyterian Church in 1854, Christian Church in 1865, First Universalist Church in 1865, Catholic Church in 1866, St. Stephen's Episcopal Church in 1867 and Lutheran Church in 1870.

In February 1874 the YMCA was formed. During the period from 1897 to 1919, seven miles of hard-surface roads were constructed. The first Fire Department was organized in 1874, the first Police Department in 1899 and the first City Hall was built in 1911.

In the late 19th century, Newton's growth was fueled by the development of coal mines in the region. The first significant mine in the area was the Couch mine of the Jasper County Coal and Railway Company, opened in the 1870s. It was, for a while, the largest mine in the county, producing 70 tons per day. William Snooks opened a mine near Newton in 1886. In the early 20th century, large scale mining in the Newton area had declined, but there were still several mines in the area that were worked intermittently.

Over the years Newton has been home to cigar factories, manufacturing of patent medicines and ant poison, the center of advertising specialty companies, manufacturing of farm equipment and home appliances. In the 20th century, Newton was a manufacturing community, much of its growth derived from the washing machine industry. Newton became known as Washing Machine Capital of the World and was home to a Fortune "500" Company - the Maytag Corporation. The community's most distinctive landmark, the Jasper County Courthouse, was built in 1911.