James Desmond Corcoran AO (8 November 1928 – 3 January 2004) was an Australian politician who served as the 37th premier of South Australia between February and September 1979, following the resignation of Don Dunstan. During his brief premiership Corcoran also served as state treasurer. Born at Millicent in the southeast of the state, he served in the Australian Army in the Korean War and Malayan Emergency, reaching the rank of captain, and being twice mentioned in despatches. Following his discharge in 1961, Corcoran was elected to the House of Assembly, succeeding his father Jim Corcoran – who retired at the 1962 election – as the member for the electoral district of Millicent representing the Australian Labor Party.

Corcoran was a key figure in the modernisation of the state branch of the Labor Party, which had been in opposition since 1933. When the party gained power in 1965, Corcoran was allocated the portfolios of irrigation, lands and repatriation in the government of Frank Walsh. Upon Walsh's retirement in 1968, Corcoran contested the party leadership but was defeated by Dunstan. In the Dunstan cabinet, Corcoran retained responsibility for irrigation and lands, and replaced repatriation with immigration. In March 1968, he became the first formally appointed deputy premier of the state, and gained the tourism portfolio. Two months later, Labor lost government and Corcoran nearly lost his seat, but retained his role as Dunstan's deputy.

At the 1970 state election, Labor returned to the government benches, and Corcoran regained his position as deputy premier, and took up the marine and works ministries. Dunstan and Corcoran had very different styles, but they formed a strong and respectful partnership. From 1975, unfavourable redistributions caused Corcoran to shift to metropolitan seats, first Coles, then from 1977, Hartley, which he held until 1982. Following the 1977 state election, he gained the environment portfolio, retaining marine and works. After Dunstan's resignation, Corcoran became premier and decided to call an early election to gain a personal mandate, buoyed by polling. This proved unwise, as the campaign went badly, business groups and media openly supported the opposition Liberal Party, and Labor lost office. Having retained Hartley, Corcoran resigned as Labor leader and did not contest the 1982 election. Dunstan was angry with Corcoran for wasting a full year of the term of government they had won in 1977, and because he had not continued to pursue Dunstan's policies on industrial democracy and Aboriginal land rights.

Made an Officer of the Order of Australia in 1982 in recognition of his service to politics and government, Corcoran was also awarded the Centenary Medal in 2001. He died in 2004 following a long illness, and was granted a state funeral. Described as a larger than life character who was respected on both sides of politics, Corcoran's long and successful partnership with Dunstan was a hallmark of his political life.

James Desmond "Des" Corcoran was born on 8 November 1928 in Millicent, South Australia. He was the youngest of nine children of Jim Corcoran and his wife Teresa Catherine née Sutton. Jim had served as a corporal in the 27th Battalion of the Australian Imperial Force on the Western Front during World War I, and had been wounded during the Battle of Amiens in August 1918. Des attended Tantanoola Primary School, but left school at 13 and worked in a bakery. He joined the Australian Labor Party (ALP) in 1941. His mother died when he was 16, and around that time he and his older brother Robert embarked on a working holiday around Australia. While in Wollongong in New South Wales, they saw an advertisement for men to enlist in the Australian Army to fight in the Korean War, and after tossing a coin to decide what to do, they both went to enlist.

In the meantime, following his unsuccessful attempt to be elected to the electoral district of Victoria in the South Australian House of Assembly in a by-election in 1932, Jim Corcoran was also unsuccessful in the state elections of 1933 and 1944, before finally prevailing in a by-election in September 1945. He was unsuccessful in his bid to be re-elected in the 1947, and 1950 state elections.

Robert served in Korea as a Royal Australian Army Ordnance Corps sergeant with the 3rd Battalion, Royal Australian Regiment in 1951–1952. Des was allocated the service number 23934, and allotted as an infantry soldier and posted to the 1st Battalion, Royal Australian Regiment (1 RAR). The battalion trained at Ingleburn, New South Wales, then embarked at Sydney on 3 March 1952 and sailed for Japan on the troop transport MV Devonshire, arriving in Kure on 18 March. After further training, 1 RAR was transported to Korea aboard the Empire Longford and disembarked in Korea on 1 June to join the 28th Commonwealth Infantry Brigade. The following month the battalion was detached to the British 29th Infantry Brigade, and relieved units on Hills 159, 210 and 355. Its duties included general patrolling along the Jamestown Line, a series of static defensive positions just north of the 38th Parallel (38°N) along which the earlier mobile war had settled into trench warfare. Its main tasks were securing defences, repairing minefield fences, and conducting reconnaissance of enemy positions to gather information.

By early December 1952, Des was a corporal and temporary sergeant in D Company when a four-man patrol was negotiating an enemy minefield. One of the men initiated a mine and was killed by the resulting explosion, which wounded two others. The unwounded soldier ran back to friendly lines for assistance, and Corcoran came forward under enemy mortar fire, dragged and carried the wounded men in, and then brought in the body of the dead soldier. For his "courage and skill in evacuating casualties through minefield gaps", and as a patrol commander in 1 RAR, Corcoran was mentioned in despatches. While Des was still serving in Korea, his father Jim was again elected to the district of Victoria in the March 1953 state election. Des returned to Australia in March 1954, and after several weeks of leave, was posted to New Guinea.