Juneau was laid down by the Federal Shipbuilding and Drydock Company in Kearny, New Jersey, on 15 September 1944; launched on 15 July 1945; sponsored by Mrs. B. L. Bartlett; and commissioned 15 February 1946.

On 22 April, she became flagship for Rear Admiral J. M. Higgins, Commander Cruiser Division 5 (CruDiv 5), and reported for duty in Yokosuka, Japan on 1 June, where she began surveillance patrols in the Tsushima Straits.

When the Korean War broke out on 25 June, Juneau was one of the few ships immediately available to Vice Admiral C. Turner Joy, Commander of Naval Forces, Far East.

On 18 July, Juneau's force, which included British units such as the Royal Navy light cruiser HMS Belfast, laid down a deadly barrage on enemy troop concentrations near Yongdok which slowed down the North Korean advance southward.

[3][4] The ship departed Sasebo Harbor on 28 July and made a sweep through the Formosa Straits before reporting for duty with the 7th Fleet at Buckner Bay, Okinawa, on 2 August.