Following shakedown, Rodman, assigned to Task Force 22 (TF 22), alternated training and patrol duties at NS Argentia, Newfoundland with screening and plane guard services for the aircraft carrier Ranger as that carrier trained aviation personnel along the northeast U.S. coast and ferried planes of the Army's 33rd Pursuit Squadron to Accra on the Gold Coast from 22 April to 28 May 1942.

Detached in June, she departed Newport 1 July, escorted a seven-troopship convoy to the Firth of Clyde, then continued on to Orkney where, as a unit of TF 99, she commenced operations with the British Home Fleet.

Based at Scapa Flow into August, she alternated patrols from Scotland and Iceland to protect the southern legs of the PQ/QP convoy lanes between those two countries and the north Russian ports of Murmansk and Archangel.

Toward the end of July, Rodman was designated to assist in filling the increasing immediate logistics demands of the Russians, and of British and American personnel in northern Russia, and to prepare for bases, men, and equipment to provide air cover for the convoys when they resumed.

On 17 August Rodman, with the cruiser Tuscaloosa and two other American destroyers departed Scapa Flow carrying medical personnel and supplies men, and equipment for the Royal Air Force's 144 and 145 Squadrons, ammunition, pyrotechnics, radar gear drystores, and provisions.

The ships offloaded, refueled, took on merchant sailors survivors of ill-fated convoys, and departed Vaenga Bay on 24 August.

On 25 October she sortied with Task Group 34.2 (TG 34.2) to support the amphibious force of TF 34 in Operation Torch, the invasion of North Africa.

On 7 November, Task Unit 34.2.3 (TU 34.2.3), comprising the escort carrier Santee, destroyer Emmons, and Rodman left TG 34.2 and screened the Southern Attack Group to its destination.

Into the summer she and her sister ships patrolled out of Scotland and Iceland and screened the larger ships of the combined force, including the battleships HMS Duke of York, USS South Dakota, and USS Alabama, as they attempted to draw the German fleet — particularly the battleship Tirpitz — out of the protected fjords.

Detached in October, she departed Norfolk 3 November for Bermuda whence she sailed in the advance scouting line screening the battleship Iowa then carrying President Franklin D. Roosevelt on the first leg of his journey to the Teheran Conference.

On 1 May she arrived at Mers-el-Kebir, whence she operated as a unit of TG 80.6, a hunter-killer group formed to work with the North African coastal air squadrons against the U-boat menace to shipping in the 325-mile stretch between the Straits of Gibraltar and Oran.

The Anglo-American air-sea effort, devised to keep U-boats submerged to the point of exhaustion and then overwhelm them as they surfaced, required time and patience, as well as coordination.

Rodman, detached on arrival in the assault area, joined TG 122.4 and through 16 June provided gunfire support and patrolled in the Baie de la Seine.

Rodman returned to England the same day, proceeded to sea again on 30 June; and, after a 3-day stop at Belfast, got underway for the Mediterranean to participate in Operation Dragoon ("Anvil"), the invasion of southern France.

Two days later French warships joined the formation; and on 15 August, the force arrived off the Delta assault area in the Baie de Bougnon.

From 7 April to 5 May Rodman underwent temporary repairs at Kerama Retto, then started her journey back to the United States.

Arriving at Charleston Navy Yard on 19 June, her repairs were completed in mid-October, and on the 22nd she sailed for Casco Bay for refresher training.