William H. Fulton was born in Indiana on March 12, 1832. We don't know anything more about his birth, his parents, or his childhood, but we do have some leads. Our first encounter with William after his birth is his marriage to Timanza Cox in Lawrence County, Indiana on 22 February, 1854. By 1860 he and Timanza were in adjacent Orange County, Indiana, with their children Nancy, Hugh, and Maria. Nancy had been born in Lawrence County in December 1854, and Hugh had been born in Orangeville, Orange County in October 1857, so we can guess that they moved to Orangeville between the births of Nancy and Hugh.
On 16 August 1862, William enlisted in the 81st Indiana Infantry, and served as a private in Company F. The 81st is known to have pushed through Kentucky in October 1862, and then experienced a string of successes in Tennessee from November 1862 until September 1863. They then pressed into Georgia.
On September 19-20, 1863, Union forces, among them them the 81st, were defeated at Chickamauga, Georgia. This may have been the point at which William was taken prisoner and imprisoned at Andersonville, Georgia.