William T. Anderson was born in 1840 in Hopkins County, Kentucky, to William C. and Martha Anderson. His siblings were Jim, Ellis, Mary Ellen, Josephine and Janie. His schoolmates remembered him as a well-behaved, quiet child. During his childhood, Anderson's family moved to Huntsville, Missouri, where his father got a job on a farm, and the family became well-respected. In 1857, they moved to the Kansas Territory, going southwest on the Santa Fe Trail and settling east of Council Grove.