Casey joined the Australian public service in 1924 to work at Whitehall as a liaison officer with the British administration.

His father, also named Richard Gardiner Casey, was a wealthy pastoralist and Member of the Queensland Legislative Assembly of Irish descent.

His mother, Evelyn, was the daughter of George Harris, another wealthy pastoralist and Member of the Queensland Legislative Council.

[1] At the outbreak of the First World War in 1914, Casey joined the Australian Imperial Force, receiving a commission as a lieutenant in the 3rd Infantry Brigade on 14 September.

[2][3] He was a member of the first convoy on board the Orvieto, and was the responsible officer looking after the German prisoners from the SMS Emden following the Battle of Cocos until the ship reached Colombo.

Casey related a story in 1967 in speech delivered at Gallipoli of a British officer being rescued by a Turkish soldier.

Casey moved to Cairo in 1942 when Winston Churchill appointed him Minister-Resident for the Middle East, to the annoyance of Prime Minister John Curtin and some in the British Foreign Office.

In 1944, when the Middle East ceased to be a military theatre, the British government appointed Casey as the Governor of Bengal, in India, a post which he held till 1946.

He was persuaded to become Federal President of the Liberal Party in September 1947 and proved to be a very effective fundraiser, partly as a result of his past social and business connections.

The Liberals won the 1949 election, and Casey returned to the House of Representatives as Member for the outer Melbourne seat of La Trobe.

In March 1950 he became Minister for National Development, gaining functions from Eric Harrison's abolished portfolio of Postwar Reconstruction and losing supply to Howard Beale.

In 1951, when the Minister for External Affairs, Percy Spender (another Menzies rival), was dispatched to the Washington embassy, Casey succeeded him.

Casey was also Minister in charge of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) from March 1950, and he was committed to its success.

On 16 May 1960 Casey was created a life peer of the British House of Lords, on the recommendation of the British prime minister, Harold Macmillan, taking the title Baron Casey, of Berwick in the State of Victoria and Commonwealth of Australia and of the City of Westminster,[11] having resigned from the ministry and parliament in February.

This was the first time a non-Labor prime minister had recommended an Australian for the post, but it also marked the end of the appointment of non-Australians to the office of Governor-General.

[12] According to William McMahon, Prime Minister Harold Holt (Menzies' successor) considered having Casey dismissed from the governor-generalship, and went as far as to have the necessary documents drawn up.

This was because Casey had twice called McMahon into Yarralumla to give him a "dressing down" over his poor relationship with Deputy Prime Minister John McEwen, which he believed was affecting the government.

Casey never fully recovered from a car accident in 1974, and died on 17 June 1976 at St Vincent's Hospital, Fitzroy, survived by his wife, daughter and son.

A private landing strip was constructed at the stud farm "Edrington" near Berwick owned by Maie and her brother Rupert Ryan.

Casey received a Military Cross, was appointed a Companion of the Distinguished Service Order (DSO) and was twice Mentioned in Despatches during the First World War.

In 1960, he was created "Baron Casey, of Berwick in the State of Victoria and the Commonwealth of Australia, and of the City of Westminster",[22] becoming the second (and last) Australian politician (after Stanley Bruce) to be elevated to the House of Lords (Sir John Forrest is sometimes mentioned in such lists, however his peerage was never formally established).