Originally laid down as HMS Marlion by J. Samuel White at East Cowes on the Isle of Wight, the vessel was renamed before being launched on 20 November 1915.

At the Battle of Jutland, the destroyer was initially cover for the seaplane tender Engadine but soon joined the action as part of a flotilla led by the light cruiser Champion.

Moresby attacked the German fleet with torpedoes, initially unsuccessfully targeting the dreadnought battleship Markgraf and, near the end of the battle, unleashing another which narrowly missed the battlecruiser Von der Tann.

The remit was to have a maximum speed of 36 knots (67 km/h; 41 mph) and, although the eventual design did not achieve this, the greater performance was appreciated by the navy.

The destroyer carried 296 long tons (301 t) of oil, giving a design range of 3,450 nautical miles (6,390 km; 3,970 mi) at 15 knots (28 km/h; 17 mph).

[10] Marlion was laid down by J. Samuel White at East Cowes on the Isle of Wight on 1 January 1915 with the yard number 1456, and launched on 20 November.

[22] The destroyer also narrowly escaped an attack from the light cruiser Wiesbaden, two torpedoes streaking past, one ahead and the other astern.

[23] As the battlesfleets broke apart, Champion sped away in pursuit of the German fleet, leaving the majority of the destroyers behind, with only Moresby and Obdurate able to keep up.

[31] The vessel served as a convoy escort, and on 2 October 1917, was also involved in the ultimately unsuccessful efforts to save the armoured cruiser Drake.

[32] On 15 March the following year, the destroyer was patrolling with sistership Michael when they surprised U-110 shortly after the submarine had sunk the ocean liner Amazon.

[33] After the Armistice of 11 November 1918 that ended the war, the Royal Navy returned to a peacetime level of strength and both the number of ships and personnel needed to be reduced to save money.