Ludlow commissioned at a time when the North Atlantic saw daily evidence of the struggle of British ships and planes against German U-boats.

Having completed shakedown, Ludlow left Boston in October 1941 for Newfoundland and Iceland, convoying supplies ultimately destined for the British Isles.

The 7 December attack on Pearl Harbor, and the declaration of war between Germany and the United States soon lengthened Ludlow's convoy runs to include the ports of Derry, Liverpool, Greenoch, and Freetown, South Africa.

Assigned to Task Force 34 (TF 34) for the invasion of North Africa, Ludlow arrived off Cape Fedhala, French Morocco, late 7 November 1942.

A 6-inch shell struck her forward and straddling shots were falling close aboard when Augusta and Brooklyn — arrived and helped to dispose of the French ships.

Ludlow returned to New York to repair battle damage, then conducted training off the coast of Maine before departing 14 January 1943 for the first of three convoy runs to Casablanca.

Heavy air attacks marked the following days and, in less than a week, Ludlow splashed two bombers one fighter, and three rocket glider bombs.

While on coastal fire support missions around Monaco, she encountered not only floating mines and E-boats, but also attacks by explosive-laden boats and human torpedoes.