Soon after being assigned to Cruiser Division 8 (CruDiv8), Atlantic Fleet, Quincy was ordered to Mediterranean waters on 20 July 1936, to protect American interests in Spain during the height of the Spanish Civil War.

[4] Quincy returned to the Boston Navy Yard on 5 October for refit preparatory to final acceptance trials which were held from 15–18 March 1937.

After an overhaul at Mare Island Navy Yard, Quincy resumed tactical operations with her division off San Clemente, California, until her redeployment to the Atlantic on 4 January 1939.

[4] Quincy transited the Panama Canal on 13 January bound for Guantanamo Bay where she engaged in gunnery practice and amphibious exercises.

Quincy later made a South American goodwill tour from 10 April to 12 June, and upon returning to Norfolk, embarked reservists for three training cruises from 9 July to 24 August.

[4] Quincy was occupied in Atlantic Fleet maneuvers and landing force exercises off Culebra Island, Puerto Rico from 3 February to 1 April 1941.

With the growth of hostilities in Europe, she was ordered to Task Force 2 (TF 2) and operated with Wasp in the mid-Atlantic, preserving US neutrality from 26 April to 6 June.

[4] Quincy returned on 25 January 1942 to Icelandic waters on convoy duty with TF 15 and made a patrol in the Denmark Straits from 8–11 March.

[4] Prior to the Marine assault on Guadalcanal on 7 August, Quincy destroyed several Japanese installations and an oil depot during her bombardment of Lunga Point.

In the Pilot House itself the only person standing was the signalman at the wheel who was vainly endeavoring to check the ship's swing to starboard to bring her to port.

On questioning him I found out that the Captain, who at that time was laying [sic] near the wheel, had instructed him to beach the ship and he was trying to head for Savo Island, distant some four miles (6 km) on the port quarter.