They were armed with a battery of twelve 14-inch (360 mm) guns in four three-gun turrets. Tennessee served in the Pacific Fleet for duration of her peacetime career. She spent the 1920s and 1930s participating in routine fleet training exercises, including the annual Fleet Problems, and cruises around the Americas and further abroad, such as a goodwill visit to Australia and New Zealand in 1925
Tennessee was moored in Battleship Row when the Japanese attacked Pearl Harbor on 7 December 1941, which brought the United States into World War II. She was not seriously damaged, and after being repaired she operated off the West Coast of the US in 1942. In 1943, Tennessee and many of the older battleships were thoroughly rebuilt to prepare them for operations in the Pacific War and in June–August, she took part in the Aleutian Islands Campaign, providing gunfire support to troops fighting to retake the islands. The Gilbert and Marshall Islands campaign followed from November 1943 to February 1944, including the Battles of Tarawa, Kwajalein, and Eniwetok. In March, she raided Kavieng to distract Japanese forces during the landing on Emirau, and from June through September, she fought in the Mariana and Palau Islands campaign, bombarding Japanese forces during the Battles of Saipan, Guam, Tinian, and Anguar.
The Philippines campaign followed in September, during which the ship operated as part of the bombardment group at the Battle of Leyte. The Japanese launched a major naval counterattack that resulted in the Battle of Leyte Gulf, a series of four naval engagements. During the Battle of Surigao Strait, Tennessee formed part of the US line of battle that defeated a Japanese squadron; this was the last battleship engagement in history. Tennessee shelled Japanese forces during the Battle of Iwo Jima in February 1945 and the Battle of Okinawa from March to June. During the latter action, she was hit by a kamikaze but was not seriously damaged. In the final months of the war, she operated primarily in the East China Sea, and after Japan’s surrender in August, she participated in the occupation of Japan before returning to the US late in the year. In the postwar draw down of naval forces, Tennessee was placed in the reserve fleet in 1946 and retained, out of service, until 1959, when the Navy decided to discard her. The ship was sold to Bethlehem Steel in July and broken up for scrap.