William Bennett was born on January 25, 1835, in Indiana to Samuel Bennett and Anna Douglas. His father was a farmer who owned $2,000 of real estate by 1850. He grew up and attended school in Indian Creek, Indiana.
He married Sarah Jane Taylor in the 1850s, and they had at least five children: Nancy, born around 1860; Samuel, born around 1862; Robert, born around 1863; Viola, born around 1872; and Sarah, born around 1872. They lived in Curryville, Indiana, and Bennett worked as a farmer. In 1860, they owned $200 of personal property.
They moved to Clear Creek, Indiana, in the 1860s. By 1870, he owned $5,000 of real estate and $250 of personal property. His wife died in the late 1800s. He remained in Clear Creek for the rest of his life, and he died in Harrodsburg, Indiana, on June 2, 1920.