The ship took part in the Dunkirk evacuation in 1940 and the Normandy landings in 1944, spending most of the rest of the war operating on the East coast of Britain.

[4] The ship's machinery consisted of four Yarrow boilers that fed steam at 250 pounds per square inch (1,700 kPa) to two sets of Parsons single-reduction geared-steam turbines, rated at 40,000 shaft horsepower (30,000 kW).

[5] Up to 504 tons of oil fuel could be carried, giving a range of 5,000 nautical miles (9,300 km; 5,800 mi) at 15 knots (28 km/h; 17 mph).

[13][14] In 1941[13] or 1942,[15] the 3-inch anti aircraft gun was moved aft to X-position, with two 20 mm Oerlikon autocannon were mounted on the ship's bridge wings.

[19] In September 1919, she deployed to the Baltic as part of the British campaign in the Baltic during the Russian Civil War, supporting the advance of Estonian forces against Petrograd (now Saint Petersburg), and taking part in a bombardment of the Bolshevik-held Krasnaya Gorka fort, together with the monitor Erebus, the cruisers Delhi and Dunedin, the leaders Shakespeare and Spenser and four destroyers on 27 October.

[25][26] Mackay left the Mediterranean for British waters in March 1933, joining the 2nd Submarine Flotilla based at Devonport in April 1933.

[36][37] On 17 January 1940, Mackay, part of the escort for Convoy OB 74, rescued the crew of the merchant ship Cairnross, sunk by a mine near Liverpool.

On completion of this refit, in April 1941, Mackay joined the 16th Destroyer Flotilla based at Harwich,[22] mainly operating in the North Sea, with duties including escorting convoys off the East coast of Britain.

[13] On 12 February 1942, Mackay, along with Whitshed, Walpole, Worcester of the 16th Flotilla and Campbell and Vivacious of the 21st Destroyer Flotilla, was exercising off Harwich, when the six ships were ordered to intercept the German battleships Scharnhorst and Gneisenau and the heavy cruiser Prinz Eugen, which were heading up the English Channel from France towards Germany in what became known as the Channel Dash.

Walpole turned back due to mechanical problems before the remaining ships encountered the German force off the Scheldt estuary.

Mackay formed part of the distant cover force (led by the battleships Anson and Duke of York) for PQ 18 and QP 14, before returning to Harwich on 27 September 1942.

[50][51] On 21 December, Mackay was again detached to carry out screening operations with the Home Fleet, to cover for more modern destroyers that were deployed elsewhere.

[22][53] On the night of 5/6 January 1944, Mackay was escorting Convoy WP 457, running between the Bristol Channel and Portsmouth, when it came under attack by seven German E-boats.

Bad weather disrupted planned air cover for the convoy, and the E-boats managed to sink three merchant ships and the naval trawler Wallasea with no loss to themselves.

[22] After the German surrender on 8 May, Mackay assisted in the Liberation of Norway, escorting, with Viceroy, nine minesweepers to Trondheim, arriving there on 17 May and visiting Bergen on 9 June.

[22] Mackay was allocated by BISCO to Metal Industries, Limited for disposal on 18 February 1947 and scrapped at their Charlestown breaking yard from June 1949.