Thomas Harrison was born in Jefferson County, Alabama, on May 1, 1823, but was brought up in Monroe County, Mississippi. He moved to Texas in 1843 and studied law in Brazoria County. Later he returned to Mississippi, from which state he went to the Mexican War as a member of the 1st Mississippi Rifles. Living first in Houston after that war, he served a term in the Texas legislature from Harris County, and then settled permanently in Waco. As captain of a volunteer militia company, he served for a time in West Texas, later entering the Confederate Army with his company in the 8th Texas Cavalry, better known as "Terry's Texas Rangers." He was promoted colonel just prior to the battle of Murfreesboro. His regiment served with Wheeler's command at Chickamauga and during the subsequent campaigns in Georgia and the Carolinas. He was appointed brigadier general in the last months of the war, to rank from January 14, 1865. Returning to Waco after the close of hostilities, General Harrison was elected district judge and was a Democratic Presidential Elector in 1872. His death occurred on July 14, 1891 at Waco, where he is buried. He was a brother of General James E. Harrison.
Ref: Generals in Gray, Lives of the Confederate Commanders by Ezra J. Warner. Printed by Louisiana State University Press, Baton Rouge and London.