Jacob H. Smith was born around 1845 in Indiana to Nathan Smith and Clarissa Watkins. His father was a farmer who owned $1,500 of real estate and $500 of personal property by 1860. The family lived in Union, Indiana, until the 1850s, when they moved to Franklin, Indiana. He probably enlisted in the Union army on November 3, 1864, and mustered in as a private in the 10th Indiana Light Artillery the following day. He probably died in a hospital in Chattanooga, Tennessee, on February 1, 1865, after being shot in the chest.