John McEwen was born on 29 March 1900 at Chiltern, Victoria. Orphaned as a child, he was brought up by his grandmother in Wangaratta and educated at state schools. McEwen joined the Attorney-General's Department on 17 April 1916 as a Clerk in the Crown Solicitor's Office in Melbourne. He enlisted in the Australian Imperial Force on 9 August 1918 but was demobilized on 24 December 1918 without active service overseas. 

After working on dairy farms in Gippsland and the Western District of Victoria, McEwen took up an 86-acre soldier settlement block at Stanhope. He joined the Victorian Farmers' Union and became active in the Victorian Country Party. On 21 September 1921 he married Annie M McLeod. In the same year Stanhope district farmers formed the Stanhope and District Co-operative Dairy Company and took over the local cheese factory, McEwen becoming Chairman of Directors and the second largest shareholder.

McEwen unsuccessfully campaigned for a seat in the State Parliament in 1932. He was elected to the Federal House of Representatives as the Member for Echuca at the election of 15 September 1934. McEwen had campaigned as a member of the Victorian Country Party but after his election supported the Federal Country Party, despite an earlier written pledge not to do so. He was expelled from the State Party in 1937 for his failure to withdraw from the Lyons-Page coalition, and joined the Federal Country Party where he remained for the rest of his political career. 

From 1935 to 1936 McEwen was a member of the House of Representatives Bankruptcy Legislation Committee. Following the redistribution of his old seat of Echuca, McEwen was elected as the Country Party Member for Indi on 23 October 1937. After unsuccessfully standing for the Leadership of the Country Party, he became Minister for the Interior [I] (CA 27) on 29 November 1937, losing this portfolio on 26 April 1939. From 14 March 1940 to 28 October 1940 he was the Minister for External Affairs [II] (CA 18) and played a leading role in the Gaullist takeover of New Caledonia. Following A W Fadden's appointment as Treasurer, McEwen was Minister for Air (CA 35) and Minister for Civil Aviation (CA 29) from 28 October 1940 to 7 October 1941. He was a member of the War Cabinet (CA 1468) in 1940 and 1941 and a member of the Australian Advisory War Council (CA 495) from 16 October 1941 until 31 August 1945. 

In September 1943 McEwen stood unsuccessfully for the leadership of his Party but was elected as Deputy Leader under A W Fadden. He was a member of the House of Representatives Standing Committee on Privileges (CA 724) from 7 March 1944 to 4 December 1947 and acted as a Consultant to the Australian Delegation to the United Nations Conference on International Organization in San Francisco during April 1945. 

McEwen was returned to Parliament in the general election of 10 December 1949 as the first Member for Murray, after the redistribution of his former electorate of Indi. He was appointed as Minister for Commerce and Agriculture (CA 48) on 19 December 1949 and represented the Commonwealth Government at the meeting of the International Wool Study Group in London during October 1950. He visited the United Kingdom from August to November 1951 for negotiations on food contracts and represented Australia at a meeting of Commonwealth Ministers on supply and production problems relating to raw materials. Between November and December 1952 he was Australian Representative at the Commonwealth Financial and Economic Conference in London. He was appointed as Privy Counsellor in 1953 and led the Australian Delegation to the GATT talks in Geneva during October and November 1954, with the Hon N O'Sullivan.  

On 11 January 1956 McEwen was appointed Minister for Trade (CA 64). Between June and July of that year he attended the Conference of Commonwealth Prime Ministers in London and conducted the renegotiation of the United Kingdom-Australia Trade Agreement. He visited Geneva in 1956 during negotiations for a new International Sugar Agreement. In 1957 he led the negotiation of the Japan-Australia Agreement on Commerce, later visiting Malaya and Ceylon for trade negotiations. 

John McEwen became Leader of the Country Party and thus Deputy Prime Minister on 26 March 1958. McEwen acted as Prime Minister in the Prime Minister's absence on a number of occasions. 

From 23 August to 6 October 1958 he led the Australian delegation to the Commonwealth Trade and Economic Conference in Montreal and conducted trade talks in Washington during April 1959. He visited New Zealand for trade discussions from July to August 1960 and was Acting Treasurer from 29 September to 13 October 1960 during the absence overseas of the Rt Hon H E Holt (CP 27). From 14 March 1962 until his retirement from Parliament in 1971, McEwen was a member of the Australian Agricultural Council (CA 479) and of the Standing Orders Committee of the House of Representatives. In March and April 1962 he visited the United States, Canada, the United Kingdom and Europe for discussions on the effect of Australia's trade of Britain's entry into the European Economic Community. During the absence overseas, from 28 May to 3 July 1962, of the Hon Sir Garfield Barwick, McEwen acted as Minister for External Affairs [II]. 

He accompanied the Prime Minister to the Conference of Commonwealth Prime Ministers in London during September 1962. McEwen visited New Zealand, Canada, the United States, Britain and Europe in April and May 1963 for trade discussions; holding trade talks in Hong Kong, Japan and the Philippines during July and August 1963.

On 17 December 1963 McEwen became Minister for Trade and Industry (CA 66) with the renaming of his department. During 1964 he attended the inauguration of the Papua New Guinea House of Assembly, the Commonwealth Trade Ministers' Conference in London and the United Nations Conference on Trade and Development held in Geneva during March and April. He was Acting Minister for Defence [III] from 19 January to 27 February 1965 and Acting Minister for External Affairs [II] from 12 June to 4 July 1965. During May and June 1966 he visited the United States, Poland and Bulgaria for trade talks and attended the Commonwealth Trade Ministers' Meeting in London.

During February 1967 McEwen visited New Zealand for the Australia-New Zealand Trade Agreement talks. In April and May he had discussions with British Ministers in London, attended the final round of GATT negotiations in Geneva and visited Rumania to sign a Trade Agreement. He was present at the OECD Ministerial Council meetings in Paris and the Trade Ministers' Meeting of GATT in Geneva. In September 1967 he visited Hungary for trade talks. From 28 September of that year, until his retirement, he was a member of the Joint Committee on a New and Permanent Parliament House.

Following the presumed drowning of Prime Minister Holt (CP 27) on 17 December 1967, McEwen was Prime Minister from 19 December 1967 to 10 January 1968. At a Press Conference on 19 December 1967 McEwen stated that "I have told McMahon that neither I nor any Country Party colleagues would be prepared to serve under him as Prime Minister", leading to the election of the Rt Hon John Gorton (CP 136) as Leader of the Liberal Party and Prime Minister.

During February 1968 McEwen visited Tokyo for trade discussions and led the Australian Delegation to the United Nations Conference on Trade and Development in New Delhi.

On 26 July 1968 McEwen married his Private Secretary, Mary Byrne. His first wife had died in February 1967 after a long illness. He was made a Companion of Honour in 1969.

On 5 February 1971, McEwen resigned from Parliament and was appointed a Knight Grand Cross of the Order of St Michael and St George. Sir John retired to his farm, now totalling over 3000 acres, and after this was sold in 1975, lived in Toorak, Victoria. He was awarded the Order of the Rising Sun (First Class) by the Japanese Government in 1973. 

Sir John died on 20 November 1980.

Sources
C. J. Lloyd, 'McEwen, Sir John (1900–1980)', Australian Dictionary of Biography, National Centre of Biography, Australian National University, http://adb.anu.edu.au/biography/mcewen-sir-john-10948/text19455, published first in hardcopy 2000, accessed online 15 September 2020.

Commonwealth Parliamentary Handbook, 16th edition, 1968

Unregistered agencies associated with person

1935-1936: House of Representatives Bankruptcy Legislation Committee - Member
2 Oct 1942-11 Feb 1943: Joint Select Committee  on the Commonwealth Bank Bill - Member
Mar 1964-Apr 1964: Commonwealth Trade Ministers Conference, London - Delegate
Sep 1965-Oct 1965: International Sugar Agreement Conference, Geneva - Leader of Australian Delegation