William Long was born on August 2, 1843, in Tennessee to George and Rebecca Long. His father was a farmer who owned $2,000 of real estate and $250 of personal property by 1860. He grew up near George Britton, and the two probably became friends. He enlisted in the Confederate army on March 18, 1862, and he mustered in as a sergeant in the 39th Tennessee Mounted Infantry. He was captured on July 4, 1863, as part of the Confederate garrison at Vicksburg, Mississippi. He was paroled on July 10, 1863.
Long returned to Hawkins County after leaving the army, and he married Eliza Thomas there on November 28, 1867. They had at least two children: John, born around 1868; and George B., born around 1870. He worked as a farmer, and by 1870, he owned $265 of personal property. They moved to Sequatchie County, Tennessee, in the late 1800s. He remained there for the rest of his life, and he died of “organic heart disease” in Lewis Chapel, Tennessee, on March 21, 1926.