Samuel J. Williams was born in 1831 in Montgomery, Virginia, and was a farmer in Selma, Indiana before the war.

On July 29, 1861 he became captain of Company K of the 19th Indiana Infantry. By the time of the Battle of Gettysburg in July of 1863 he had risen to colonel and commanded the regiment.

He was killed on May 6, 1864 in the Battle of the Wilderness.