Hesperus was damaged by German aircraft during the Norwegian Campaign in May 1940 and was assigned to convoy escort and anti-submarine patrols after her repairs were completed.

She was converted to an escort destroyer in early 1943 after suffering damage from one of her two ramming attacks that sank German submarines.

The turbines developed a total of 34,000 shaft horsepower (25,000 kW) and gave a maximum speed of 36 knots (67 km/h; 41 mph).

Hesperus carried a maximum of 470 long tons (480 t) of fuel oil, giving her a range of 5,530 nautical miles (10,240 km; 6,360 mi) at 15 knots (28 km/h; 17 mph).

[4][5] Hesperus was completed without a director-control tower (DCT) so the three remaining 4.7-inch low-angle guns fired in local control using ranges provided by a rangefinder.

[7] The ship received a HF/DF radio direction finder mounted on a pole mainmast[3] and a Type 286 short-range surface-search radar during her mid-1941 refit.

[7] During the Norwegian Campaign, Hesperus transported elements of the Scots Guards to Mo i Rana on 15 May[14] and was damaged by near misses from Junkers Ju 87 dive-bombers that same day.

[16] After repairs, she resumed her convoy escort duties until April when she was assigned to Force H in Gibraltar whilst Macintyre transferred to the destroyer Walker in March.

Hesperus was transferred out of Force H as her anti-aircraft capability was believed by Admiral James Somerville to be too weak for operations in the Mediterranean.

[7] In August 1941, Hesperus was one of the destroyers that escorted the battleship Prince of Wales carrying Prime Minister Winston Churchill to the Atlantic Charter meeting with President Franklin D. Roosevelt at Placentia Bay.

[8] Upon their completion Hesperus rejoined the 9th Escort Group[7] before she was attached to Force H in December for convoy duties at Gibraltar.

[8] Together with her sister Harvester, Hesperus sank the German submarine U-208 on 7 December 1941 in the Atlantic west of Gibraltar.

Although a glancing hit, the collision was so violent that it flung the U-boat's captain and first lieutenant from the submarine's conning tower into the motorboat stowed on the destroyer's deck.

Whilst escorting Convoy HX 219 near Rockall on 26 December, Hesperus and the destroyer Vanessa sank the German submarine U-357 by ramming.

On 30 April 1945, the ship, together with her sister Havelock, attacked the wreck of U-246 northwest of the island of Anglesey thinking that it was U-242 which had been spotted by a Short Sunderland flying boat earlier that day.

On 27 May, the ship and her sister Havelock escorted the exiled Norwegian government back to Oslo and remained there until 1 June.