His parents were William, 4th Lord Plunket, the archbishop of Dublin in 1884–97, and his wife Anne, the daughter of Sir Benjamin Guinness.

By chance, the Speaker of the New Zealand House of Representatives at the time was his second cousin Arthur Guinness.

[3] In 1907 he presented the Plunket Shield, which is still contested each year by the major cricket teams in New Zealand.

[6] Lord Plunket died on 24 January 1920 aged 55 at 40 Elvaston Place, London, and was buried in the city's Putney Vale Cemetery.

[1] Plunket married, in 1894, Lady Victoria Alexandrina Hamilton-Temple-Blackwood, youngest daughter of the 1st Marquess of Dufferin and Ava, by whom he was to have eight children.