Hewitt is at the intersection of Farm roads 2063 and 1695, eight miles southwest of Waco in south central McLennan County. It was established in 1882, when the Missouri, Kansas and Texas Railroad built the section of track between Hillsboro and Taylor and was named for George A. Hewitt, a railroad director. A Hewitt post office opened in 1884 with Thomas J. McMurray as postmaster. In the 1890s Hewitt had a gristmill, a cotton gin, a grocery, and sixty to 100 residents; grain and lumber were among the community's principal shipments. In 1895 Hewitt became the focus of an independent school district. A small state bank was organized at Hewitt in 1912, but it could not compete with banks in nearby Waco and closed voluntarily in 1916.
Population estimates for Hewitt were as high as 150 in the mid-1920s, but from the early 1930s to the mid-1960s only seventy-nine residents were reported. Three churches, two schools, a few businesses, and several residences marked the community on county highway maps in the 1940s. The Hewitt Independent School District was joined to the South Bosque Independent School District in 1947 to form the Midway Consolidated Independent School District.
Residents of Hewitt voted to incorporate in 1960 and elected George C. Baxley mayor. The population, supplemented by new residents who commuted to work in nearby Waco, rose to 286 in the late 1960s and to 630 in the late 1970s. The number of businesses increased as well, rising from seven in the mid-1960s to thirty-two by the late 1970s. Growth accelerated rapidly in the 1980s, when Hewitt was the fastest growing community in the county. In 1982 population estimates showed 5,247 residents and fifty-six businesses, and 7,474 residents and ninety-seven businesses were reported in 1988. In 1990 the population was 8,983, and in 2000 it was 11,085.