Tucker entered the Confederate Army as a captain of Company K, 11th Mississippi Infantry Regiment. He was part of Barnard Bee's brigade at the First Battle of Manassas. Soon afterwards Tucker's company was sent to the West and merged with the 41st Mississippi Infantry Regiment. Tucker was commissioned colonel of the regiment in May 1862. He led the regiment at the Battles of Perryville, Murfreesboro, Chickamauga, and Chattanooga before being promoted to brigadier general to rank from March 1, 1864. Tucker's field duty ended that summer after suffering a severe wound at the Battle of Resaca during the Atlanta Campaign. In the last weeks of the war he commanded the District of Southern Mississippi and East Louisiana.