Laid down at Federal Shipbuilding & Dry Dock Co., Kearny, N.J., 5 April 1937, Lang commissioned 30 March 1939.
She departed New York 12 August 1939 guarding President Franklin D. Roosevelt’s passage to Campobello, Newfoundland, and Nova Scotia. The President came on board the 24th at Sandy Hook, New Jersey for transit to Fort Hancock. In November, the destroyer left Newport, Rhode Island for Galveston, Texas and duty on the Gulf Patrol. Transferred to the Pacific, she reached San Diego 18 March 1940 and Pearl Harbor 2 April, where she participated in fleet problems and training exercises. She voyaged between the West Coast and Hawaii throughout the remainder of 1940 and into early 1941 engaged in escort duties and training.
In June 1941 Lang returned to the Caribbean and Atlantic coast for carrier and antisubmarine training. In December she acted as screen and plane guard during flight operations for Yorktown and Ranger off the Maine coast and Bermuda. (continued)