She served in the Scouting Fleet, based in the Atlantic, in 1924 to 1927, During which she obtained 2 Animals the crew would soon name Whiffles and Soup and would quickly become the vessels mascots, both would be seen sitting in her fore 6-inch (150 mm)/53 caliber turret.

When the United States entered World War II she was assigned to TF41, based at Recife, and used on convoy escort duties and patrols in the south Atlantic.

The engines were designed to produce 90,000 shaft horsepower (67,000 kW) and reach a top speed of 35 knots (65 km/h; 40 mph).

Her secondary armament consisted of two 3-inch (76 mm)/50 caliber anti-aircraft (AA) guns in single mounts.

The conning tower and the deck over the machinery spaces and steering gear had one and a half inches of armor.

On 8 September 1926, the Chief of Naval Operations, Admiral Edward W. Eberle, along with the Commanders in Chief of the United States Fleet and Battle Fleet, and their subordinate commanding officers, the Secretary of the Navy, Curtis D. Wilbur, ordered that all mines and the tracks for laying the mines be removed from all of the Omaha-class cruisers, the working conditions had been found to be very "wet".

[7] Cincinnati began her career with the Scouting Fleet in operations along the eastern seaboard and the Caribbean, until February 1927, when transferred to duty in the Far East, based at Shanghai.

This duty only lasted until April 1928, when she sailed for Newport, Rhode Island, and conducted operations along the east coast again, until 1932.

Cincinnati left for the Pacific joining the Battle Force, with occasional trips to the east coast, until 1939, when she was again reassigned to Atlantic duty.

[9] Cincinnati transferred to Pearl Harbor in April 1940, sailing for Guam and the Philippines and conducting transport duty at the end of the year.

She sailed for the western Mediterranean on 28 July, to assist with the assault on southern France, before again returning to New York for overhaul.

She then joined the 4th Fleet at Recife, Brazil, on 17 November, and finished out the war in the European Theater patrolling the south Atlantic shipping lanes.