When war was declared in September 1939, all of the Le Fantasques were assigned to the Force de Raid, tasked with hunting down German commerce raiders and blockade runners.

Le Malin and two of her sister ships were based in Dakar, French West Africa, to patrol the Central Atlantic for several months in late 1939.

They returned to Metropolitan France before the end of the year and were transferred to French Algeria in late April 1940 in case Italy decided to enter the war.

After returning to the Mediterranean, she screened French cruisers several times as they unsuccessfully hunted for Italian ships after Italy declared war in June.

During her sea trials on 28 August 1935, her turbines provided 97,956 metric horsepower (72,047 kW; 96,616 shp) and she reached 42.3 knots (78.3 km/h; 48.7 mph) for a single hour.

Le Malin carried enough fuel oil to give her a range of 2,900 nautical miles (5,400 km; 3,300 mi) at 15 knots (28 km/h; 17 mph).

After the war began in September, 200 kg depth-charge stowage increased to 48 and a pair of rails were installed on the stern for 35-kilogram (77 lb) depth charges.

In May the ship was provided with an Alpha-2 sonar system in cases pending the modification of the hull to accommodate the required flexible underwater dome.

[7] During 21–30 October, the Force de Raid, including the Le Fantasques, screened Convoy KJ 4 against a possible attack by the heavy cruiser Admiral Graf Spee.

[8] In anticipation of an Italian declaration of war, the Force de Raid, including the 8th Scout Division, assembled in Mers-el-Kébir, French Algeria, on 5–9 April 1940, only to return to Brest when the Germans invaded Norway on the 10th.

On the night of 23/24 April 1940, the 8th Scout Division made a high-speed patrol of the Skagerrak, hoping to attack German merchantmen headed for Norway.

They encountered two patrol boats and damaged one of them while also engaging a pair of S-boats to little effect and narrowly missed spotting a convoy of minelayers.

In response, the Germans and Italians authorized the Vichy French to send ships to the Gulf of Guinea to bring the rebellious colonies back under control.

The destroyers lacked enough range to reach Dakar at the 24 knots (44 km/h; 28 mph) ordered by Contre amiral (Rear Admiral) Célestin Bourragué and were forced to return to Casablanca.

[11] The Vichy French destroyers were tasked to make a continuous smoke screen to protect the cruisers as they maneuvered to avoid British shells; Le Malin was not damaged during the battle.

Arriving on 26 June, Le Malin's refit lasted until 17 November and included the addition of a British Type 128 ASDIC system, installation of SA early-warning and SF surface-search radars, the removal of her aft torpedo tubes and the conversion of some boiler feedwater tanks to fuel oil to improve her range.

Le Malin supported the Allied landings at Anzio, Italy, on 22 January before the 10th LCD was tasked to conduct deep raids in the Adriatic in search of German shipping in late February.

The ships were refitted and then transferred to Alexandria, Egypt, to conduct patrols south of Crete and in the Aegean in April where they had no engagements other than a bombardment of Kos.

In June, the ship's port propeller shaft had to be removed; adapting the supporting strut from L'Audacieux proved to be a prolonged procedure as they were not identical.

On 15 August, the 10th LCD provided naval gunfire support during Operation Dragoon, the Allied landing in Provence, during which Le Malin fired 80 shells from her main guns.

Le Malin was refitted in 1951 to serve as an escort for the French aircraft carriers and attained a speed of 41 knots (76 km/h; 47 mph) during her post-refit trials on 21 August.