Louisville's shakedown cruise, running through the summer, fall, and winter of 1931, took her from Bremerton to New York City via the Panama Canal. Returning from New York, she participated in the 1932 fleet problems before commencing gunnery exercises in the San Pedro-San Diego area. During the winter of 1933, she steamed for Hawaii, returning after exercises to San Pedro where she became a schoolship for anti-aircraft training. In April 1934, the cruiser steamed out of San Diego to begin a nine-month voyage "showing the flag" at various ports in Central America, the Caribbean Sea, and along the gulf and east coasts. Arriving back in California in late fall, Louisville participated in gunnery and tactical exercises until the spring of 1935, when she departed for Dutch Harbor, Alaska, and, thence, to Pearl Harbor to take part in fleet problems.
For the next two years, she operated off the West Coast, participating in the 1936 and 1937 fleet problems, making good will calls at Latin American ports and undergoing local training operations. In January 1938, Louisville began a long Pacific cruise which took her to Hawaii, Samoa, Australia, and Tahiti before returning to Pearl Harbor for fleet problems. While in Sydney, the crew of the Louisville rescued a number of passengers from a sightseeing ferryboat which had capsized when most of the passengers crowded to the rail to wave the cruiser off.
The winter of 1939 found Louisville participating in fleet exercises in the Caribbean. She operated in these waters until May, when she returned to the west coast. After fleet problems off Hawaii that autumn, Louisville departed Long Beach, California for an extended cruise through the Panama Canal to eastern South America. At Bahia, Brazil, she received orders to proceed to Simonstown, South Africa.
As a neutral ship, Louisville traveled the U-boat-infested waters with her American flag spotlighted. At Simonstown, she received $148 million in British gold for deposit in the United States. She then sailed for New York City, delivered her precious cargo and returned to the Pacific.
World War II
On 7 December 1941, Louisville, escorting
and President Coolidge, was en route from Tarakan, East Borneo, to Pearl Harbor. She continued on to Hawaii, stopped briefly to survey the damage and proceeded on to California. There she joined Task Force 17 (TF 17) and steamed from San Diego on 6 January 1942, for Samoa, landing troops there on 22 January. Her first offensive operation of the war came on her return trip when she took part in carrier plane raids on 1–2 February on the Gilbert and Marshall Islands. During this action, she lost one of her planes.
After a short stay at Pearl Harbor, Louisville commenced patrolling the Ellice Islands area to help protect American bases in that vicinity. Early in March she joined TF 119, a carrier force, and began operations to stem the Japanese advancement down the Bismarck Archipelago and the Solomons. This force steamed in the Salamaua-Lae-Rabaul sector for a number of days, making airstrikes on numerous objectives.
Following this operation, Louisville returned to Pearl Harbor, proceeding from there to Mare Island Navy Yard, San Francisco, where her anti-aircraft armament was increased with additional 1.1in and 20mm cannons fitted. On 31 May, she steamed for the Aleutians to join TF 8 to counter the enemy forces expected to be in the area. Fortunately the Japanese carrier force did not locate her and the other cruisers during the attacks on Dutch Harbor, which coincided with the Battle of Midway. Her duties, during this period of Japan's strongest efforts to establish the northern end of her "ribbon defense" in the western Aleutians, were primarily those of convoy escort, but included shore bombardment of Kiska Island.
On 11 November, the cruiser departed San Francisco for Pearl Harbor, continuing, after a few days on to the South Pacific, escorting several troop transports as far as New Caledonia. She then proceeded north to Espiritu Santo to Join TF 67, which was then battling Japanese forces in the Solomons. On 29 January 1943, Louisville participated In the Battle off Rennell Island, the last of the seven naval battles for Guadalcanal, after which she operated east of the island until it was entirely secured.
at Aleutian Islands
In April, Louisville steamed, via Pearl Harbor, to the Aleutians. There, as a unit of TF 16, the cruiser covered the assault and occupation of Attu (11–30 May) and participated In the preinvasion bombardment of Kiska in July.
After the latter was evacuated by the Japanese, she conducted escort of convoy operations in the northern Pacific. In August 1943 she proceeded to the Mare Island Navy Yard for an overhaul to her machinery and alterations. Louisville was in overhaul at Mare Island from 8 October until 24 Dec 1943.
Like her sister ships her forward mast was cut down and her (aft) mainmast was removed and replaced with a lighter tripod just aft of the second funnel. The Louisville camouflage
measure 32-6D paint scheme was added and (2) new mark 34 main battery directors were added.
The 1.1in AA cannons were removed and replaced with several quad 40mm Bofors mounts along with numerous 20mm cannons. Improved radars and flagship spaces were also added. Following this work in January 1944, Louisville returned to the southern Pacific as the flagship of Rear Admiral J. B. Oldendorf, who was to command the naval gunfire support groups through the amphibious operations ahead. In the Marshalls at the end of the month, she bombarded Wotje Atoll, west of Kwajalein, on 29 January. Then the cruiser turned her guns on the airfield and troop concentrations on Roi and Namur on the southern tip of the atoll, contributing to the conquest of those islands by 3 February. During this campaign, while waiting bombardment further targets an 8-inch 55 caliber shell fired from the USS Indianapolis CA 35 ricocheted off the island to explode a near miss alongside Louisville starboard side causing heavy pieces of shrapnel which damaged the chiefs quarters, pierced the bulkhead, and turret No. 3 – 8-inch gun had shrapnel damage
on the tips of the barrels- no injuries. Two weeks later, Louisville led the gunfire support group into action at Eniwetok, which fell on 22 February.
After Eniwetok, Louisville joined TF 58, and with the fast aircraft carriers struck Japanese installations in the Palaus, in March, and bombarded Truk and
Sawatan in April. June brought preparations for the invasion of the greater Marianas, and again Louisville was the leading unit in shore bombardment operations; beginning with Saipan, where she fired continuously for the first 11 days of that engagement, through the shelling of Tinian, and ending with the assault on Guam. One spotting plane from Louisville was shot down by AA fire which killed the pilot and observer on July 20, 1944 at Tinian.
The Louisville had been in the battle area 59 straight days/nights in the Marianas Campaign and had fired 24,948 rounds of 8 inch ammunition.
After the Mariana Islands, Louisville retired to the rear area until mid-September, when she steamed to Palau for the preinvasion bombardment of Peleliu. Then as advanced bases were created, final preparations for the invasion of the Philippines were made. On 18 October, Louisville entered Leyte Gulf and pounded Japanese shore installations.
Louisville became the first large US ship to enter Philippine waters since 12 December 1941. On October 21, 1944 while Louisville was bombarding Leyte she was hit by the kamikaze plane shrapnel killing (1) man. On October 25, 1944, she was in the Battle of Leyte Gulf, participating in the last engagement of a battleline as the Japanese southern force attempted to force its way into Leyte Gulf through Surigao Strait. Admiral Oldendorf deployed the American battleline across the strait and PT boats and destroyers on either side of the narrow body of water, defeating the Japanese ships as they passed through the strait.
During the Battle of Surigao Strait, Louisville helped to sink the bow section of the Japanese battleship Fusō, after the battleship had broke into two from an internal explosion caused by a torpedo from the destroyer USS Melvin.
Following Leyte operations, Louisville rejoined the fast carriers now designated TF 38, and participated in preinvasion strikes against the enemy on Luzon. By the new year, 1945, Louisville was headed towards Lingayen Gulf. While en route on 5–6 January, two kamikazes headed for and scored on her. The first Kamikaze on January 5, 1945 hit the No. 2 main battery 8 inch 55 caliber gun knocking it completely out of commission killing one man with 17 injured/burned including Captain Rex LeGrande Hicks.
The second Kamikaze on January 6, 1945 hit the starboard side signal bridge.
Rear Admiral Theodore E. Chandler, commander of Cruiser Division 4 (CruDiv 4) was fatally injured helping the sailors man handle the fire hoses to put out the massive flames during the latter attack, and died of his wounds the following day. Rear Admiral William P. McCarty (then Commander) took control of Louisville and managed recovery efforts in fighting fires and restoration of equipment, for which he was awarded the Silver Star. Also killed was Admiral's Orderly Walter Joseph Siegel, who was standing by the Admiral at the time. Siegel was the only Marine killed; however, 41 Navy men were also killed and 125 or more men were wounded. Bridge knocked out of commission at the time forced switch of control to Batt no. 2 by second smoke stack. Despite extensive damage, the cruiser shelled the beaches and shot down several enemy planes before withdrawing on January 9, 1945 and proceeding to Mare Island Navy Yard for repairs.
Her repairs completed on April 10, 1945, Louisville delivered Admiral Halsey's 50 officers and 100 staff to the battleship Missouri at Guam and Louisville returned to the Pacific to join TF 54 in providing gunfire support for ground forces on Okinawa. On June 5, 1945, she was again hit by a kamikaze(Initially identified as a friendly plane). (4) twin 20 AA opened up to set the kamikaze ablaze prior to hitting the Louisville which killed 8 sailors on a quad 40 mm AA gun mount, injured 45 sailors, bent the number 1 smoke stack and cut the Louisville's seaplane off and left only the pontoon on the catapult. Louisville was back on the gun line by 9 June, to remain on station until ordered back to Pearl Harbor for repairs on 15 June.