She made her first deployment with the 6th Fleet in the ensuing months, visiting Malta; Bizerte, Tunisia; Golfe-Juan, France; Argostoli and Phaleron Bay, Greece; İskenderun, Turkey; Trieste and Venice, Italy; and Gibraltar.

Worcester operated off the eastern seaboard, ranging from Newport to Norfolk and south to Puerto Rico, with visits in between to Philadelphia, before she began her second 6th Fleet deployment in the spring of 1950.

In between her cycles of drills and exercises in the Mediterranean, Worcester visited Augusta, Sicily; Bizerte; Genoa and La Spezia, Italy; and Golfe Juan, on the southern coast of France, before she was put into Phaleron Bay on 20 July.

Accordingly, Worcester departed Phaleron Bay on 27 July, in company with Destroyer Division 21 composed of Fred T. Berry, Keppler, Norris, and McCaffery.

En route, the American warships had been diverted through the Bashi Channel to be available to counter any invasion attempt by the communist Chinese of Formosa.

On 28 August, the light cruiser—steaming in company with Norris—joined TF 77 and proceeded into the Yellow Sea for operations against enemy targets located in central and southwestern Korea.

The combat air patrol—four Vought F4U Corsairs from Valley Forge—soon reported the stranger as being a twin-engine bomber with a pointed nose, a single tailfin, and high inverted gull wings.

The following day, Worcester went to general quarters at 11:08 and commenced maneuvering at 20 knots (37 km/h; 23 mph) to avoid possible attack when her radar picked up an unidentified plane closing the formation from the east.

Three minutes later, the cruiser fired a warning shot of three rounds of 6-inch projectiles in the direction of the intruder—it turned out to be a British Short Sunderland flying boat on patrol.

There was one more day of flight operations off the Korean coast, 6 September, before Worcester transferred her helicopter to Philippine Sea to clear the ship for a practice anti-aircraft firing.

Worcester screened the fast carrier task forces as their planes dropped lethal loads on North Korean targets ashore until she was detached on 20 September to conduct a shore bombardment mission as part of TG 95.2 in the vicinity of Pohang Dong.

Directed by Korean Military Advisory Group (KMAG) personnel ashore, Worcester delivered call-fire throughout the day with pinpoint accuracy at troop concentrations and command posts.

The rapid advance of the UN forces on 26 September obviated fire support from Worcester's guns; but the cruiser received word that Brush had hit a naval mine off Tanchon, North Korea, at 12:20.

At 01:01 on 27 September, Worcester commenced taking on board the more seriously wounded of the destroyer's company via highline transfer, eventually receiving 15 stretcher cases—all men suffering from burns—by 02:28.

As she was being made fast to her buoy in Sasebo harbor, Worcester received a message from the destroyer that she had aided: "With us you are not only big league but world champions.

At 12:48 on 10 October, Worcester got underway to return to the east coast of Korea—this time to screen minesweeping operations at the port of Wonsan and to support the advance of the 3rd Republic of Korea (ROK) Army Division.

Over the next few days, Worcester and the ships accompanying her proceeded to rain destruction on targets of opportunity near Wonsan—targets that ranged from railroad marshalling yards to rolling stock and adjacent warehouse areas.

Your rapid deployment from the European station to the Far East, followed by your immediate and most effective participation in the Korean effort, clearly demonstrates that your status of war readiness was excellent."

Returning to Philadelphia on 21 November—via Pearl Harbor and the Panama Canal—Worcester later spent six days at Norfolk, 23 to 29 November, before she was overhauled at the Boston Naval Shipyard from 1 December 1950 to 20 March 1951.

During that time, she participated in fleet maneuvers and exercises and paid good-will calls on many ports—ranging from Bergen, Norway; to Copenhagen, Denmark; to Dublin, Ireland; and Portsmouth, England.