Arriving San Diego, California, 1 July, the destroyer performed exercises and tactical training operations until she sailed for Pearl Harbor 5 October 1939.

During early March she arrived in the Fiji Islands to join the expanded ASW screen which was formed to keep the South Pacific supply lines open.

After 6 months of patrol and screening operations, Lamson saw action 22 October when, with Mahan, she attacked Japanese picket boats stationed between Gilbert and Ellice Islands.

Arriving Milne Bay 19 August 1943, Lamson joined Destroyer Squadron 5, the forerunner of the mighty 7th Fleet, to engage in the New Guinea operations.

After 2 months of escort duty, Lamson joined three other destroyers 29 November and penetrated 160 miles into enemy territory to bombard Madang, the main Japanese naval base on New Guinea.

Departing Hollandia 25 October, Lamson steamed to the Philippines to serve as picket, patrol and screening ship for the massive Leyte assault.

A fitting climax to Lamson's fine war record came on 3 September, when she arrived at Chichi Jima to supervise the surrender of the Bonin Islands.