On March 3, 1863, President Abraham Lincoln signed an act calling for all able-bodied men to join the National Forces. William Barnes joined the union army the following February. He was stationed in Norfolk, Virginia and six months later was wounded in the Battle of New Market Heights on September 29-30, 1864. He was awarded the Medal of Honor for his efforts. In July of 1865, Barnes was stationed along the Texas border and was promoted to the rank of Sergeant. Barnes, assigned to the U.S. Colored Troops, was vital to the protection of the Texas government and its coastal and southern border. Barnes died of consumption in December 1866. He was buried at Indianola and then reinterred in San Antonio National Cemetery.