[2] In May 1861, Smith was elected as the colonel of a state militia regiment, the 154th Tennessee, which was soon mustered into the Confederate army.

In April 1862, he led his regiment during the Battle of Shiloh in western Tennessee, where he was disabled from a severe wound to his right shoulder, rendering it useless and forcing Smith to turn over command to a subordinate and leave the field.

During a night attack at Chickamauga, Smith and his staff inadvertently rode into Union lines, where he and two aides were struck down.

[1] His divisional commander, Maj. Gen. Benjamin F. Cheatham, reported, It was in this night attack that Brig.-Gen. Preston Smith of Tennessee received his mortal wound, from which he died in 50 minutes.

At the head of his noble brigade, of which he had been the commander as colonel and brigadier-general for two years and a half, he fell in the performance of what he himself, with his expiring breath, simply said was his duty.