Reginald Plunkett was born on 28 August 1880, the 2nd son of 17th Baron Dunsany, and Ernle Elizabeth Louisa Maria Grosvenor, only child of Colonel Francis Augustus Plunkett Burton, Coldstream Guards. Plunkett assumed the additional names of Ernle-Erle-Drax by Royal Licence in 1916, and in the same year married Kathleen, only daughter of Quintin Chalmers; they had one son and four daughters.

Plunkett was educated at Cheam School and HMS Britannia, going to sea in 1896. In 1901 he was made Lieutenant, and in 1912, Commander. Plunkett served afloat in the Grand Fleet from 1914 onwards and was present, on board HMS Lion, at the Heligoland Action, Dogger Bank, and Jutland, where he was mentioned in despatches and promoted to Captain. He was also awarded the Russian Order of St Stanislas (2nd class) with swords, in 1916, and won the DSO in 1918, when commanding HMS Blanche.

After the war, Plunkett became Director of the Royal Naval Staff College, Greenwich [London] from 1919 to 1922. He then served as President of the Naval Allied Control Commission in Berlin [Germany] in 1923 and 1924, and as Naval Aide to King George V, from 1927 to 1928. Being promoted to Rear-Admiral in 1928, Plunkett took command as Rear-Admiral in the 1st Battle Squadron, (1929-1930) before returning to shore duties as Director of the Admiralty Manning Department, (1930-32). In 1932 he was promoted to Vice-Admiral and served as Commander-in-Chief of the America and West Indies Station, (1932-34), then as Commander-in-Chief, Plymouth Station, (1935-38). Plunkett became a full Admiral in 1936, but had to wait until 1939 for a further command, when he became Commander-in-Chief, The Nore, and also First and Principal Naval Aide to King George VI, (1939-1941). He then served in the Home Guard until 1943, but ended his career as Commodore of Ocean Convoys (1943-45).

Plunkett's publications include: England’s Last Chance, (1938); Mission to Moscow, (1939); The Art of War, 20th Century Version, (1943); World War III, some pros and cons, (1954); History of Charborough, 1056-1956, (1956); Solar Heated Swimming Pools, (1962); A Few Notes on Health, Happiness and Wisdom, (1965); Quotes and Notes, (1966); The Uncertain Future, (1967).

He died on 16 October 1967.