He enlisted on May 26, 1861 at Corinth, Mississippi for 1 year. Captured at Fishing Creek, Kentucky on January 19, 1862 and sent to a Northern Prisoner of War Camp. He was later exchanged at Vicksburg, Mississippi in September, 1862. He was 5'10" tall, Black eyes, Black Hair and Dark Complexion.
Thomas was mortally wounded on November 30th and died in December, 1864. The night before the battle Capt. James T. Smith of Co. E. 15th Mississippi took a "French Leave" and snuck away for a few hours to meet with his kin who lived nearby and to procure a dinner for him and his friends. They were: Col. Michael Farrell, and Lt. Thomas W. Allen of the 15th Mississippi, Lt. Col. W. A. Rorer of the 20th Mississippi and Maj. William F. Crumpton of the 14th Mississippi. They were also joined by Lt. C. H Campbell of the 15th Mississippi.
During their campfire dinner Smith look at his friends and stated, "Well, we are going to have a hard fight, and it will be my last. I think I will be killed".
Lt. Allen said "I am ready to go. If my country requires my life, I am willing to yield it." Lt. Col. Rorer said, " If things continue as they now are, it will only be a question of time when every true Confederate who stands at his post must be killed, as we have no place to get recruits and are fighting ten to one a present. It is a mere question of time when we must all go, and I came out for that purpose."
Major William Crumpton of the 14th Mississippi agreed. Col. Michael Farrell responded, "O, well boys, that is a soldier's life. Let us not complain or shrink from it." Before the next night was out, all but Lt Campbell would be dead or mortally wounded. It was reported that "Lt. Allen, seeing Capt. Smith fall ran up by him and turning to the Company said, 'Company E follow me' , but just as soon as he turned his face to the front was shot and fell across Captain Smith".