Construction by J. Samuel White began in June 1914, shortly before the outbreak of the First World War, and the ship was launched and completed in 1915.

[4] Three sets of Brown-Curtis steam turbines were fed by four Yarrow three-drum boilers, rated at 36,000 shaft horsepower (27,000 kW), which gave a speed of 34 knots (63 km/h; 39 mph).

[6][3] Up to 515 tons of oil fuel could be carried, giving a range of 4,290 nautical miles (7,950 km; 4,940 mi) at 15 knots (28 km/h; 17 mph).

[3] Lightfoot was laid down at J. Samuel White shipyard at Cowes on the Isle of Wight on 9 June 1914, was launched on 28 May 1915 and completed on 29 May 1915.

[5] By October 1915 Lightfoot had joined the Ninth Destroyer Flotilla of the Harwich Force as second leader, replacing Tipperary.

[8][9] On 30 October Lightfoot sailed with the Harwich Force on a sweep across the German Bight, with a single Swedish merchant ship, the Osterland, laden with Iron Ore being arrested and ordered to the Humber for investigation.

Vindex launched five seaplanes on the morning of 25 March, but only two returned at the appointed time, reporting that the Zeppelin base was at Tondern rather than Hoyer, and that they had been unable to attack it.

While damage to Laverock was confined to her bows, Medusa had been holed in her engine room and was taken in tow by Lightfoot and set out for home at a speed of 12 knots (22 km/h; 14 mph).

[13][14][15][16] On 24 April 1916, a force of German battlecruisers and cruiser set out from Kiel to bombard the coastal towns of Lowestoft and Yarmouth.

[28] On 29 September the Harwich Force escorted Vindex as she launched a seaplane on a reconnaissance mission in support of a planned operations by British Coastal Motor Boats.

After an exchange of fire, the German torpedo boats turned back towards Zeebrugge, with the British destroyers setting off in pursuit and soon leaving the slower cruisers behind.

Early of 5 June Lightfoot spotted two German torpedo boats (S20 and S15) which were returning to base after a patrol.

S20 was hit in the engine room and immobilised by a shell from a British cruiser, and was finished off by the destroyers Satyr and Torrent while S15 was badly damaged but managed to successfully make it into port.

[39][40] In September 1917 Lightfoot transferred from the Harwich Force to the Sixth Destroyer Flotilla of the Dover Patrol.