Admiral Sir John Frederick Ernest Green, KCMG, CB (8 August 1866 – 30 October 1948) was a Royal Navy officer of the late 19th and early 20th centuries.

[citation needed] Green took the examination for naval cadetships successfully in July 1879,[2] and joined the Royal Navy as a midshipman in 1882.

[citation needed] Promoted to captain on 30 June 1906, Green received a commendation in 1907 for efforts he made in helping to salvage the destroyer HMS Ariel,[10] which had been wrecked on 19 April 1907 when she ran aground on a breakwater just outside Grand Harbour, Valletta, Malta.

In 1910, Forte ran aground and the Admiralty expressed "severe displeasure for failure to comply with K[ing]'s R[egulations] & for unseamanlike manner in which H[is] M[ajesty]'s ship was navigated.

A court of inquiry convened to investigate the collision conclude that Natal's speed of 10 knots (11.5 mph; 18.5 km/h) when she struck the fishing vessel was excessive for the foggy conditions, but the Admiralty declined to endorse this finding.

[18] On 30 October 1918, Green became Rear-Admiral Commanding in the White Sea during the North Russia intervention in the Russian Civil War with the battleship HMS Glory as his flagship.