A Norwood by-election was held due to the seat's election result being overturned by a court decision, which saw the seat lost from the Liberals to Labor, which meant the Liberals held 24 seats with Labor on 20 seats.
House of Assembly (IRV) — Turnout 93.04% (CV) — Informal 4.43%
Premier Don Dunstan abruptly resigned on 15 February 1979 due to ill health, and was succeeded by Deputy Premier Des Corcoran.
Spurred by positive opinion polls and seeking to escape the shadow of Dunstan, Corcoran called a snap election (without pre-informing the party apparatus) in order to gain a mandate of his own. The election campaign was plagued by problems, which allowed an opening for the Liberals under Tonkin. It didn't help matters that The Advertiser was biased toward the Liberal campaign. Labor suffered a large swing, losing eight seats to the Liberals. The Liberals also won 55 percent of the two-party vote to Labor's 45 percent. It was the first time the main non-Labor party in South Australia had won the most seats while also winning a majority of the vote since the Liberal and Country League won 50.3 percent of the two-party vote in 1959.
Corcoran was bitter in defeat, believing sections of the ALP had undermined him during the campaign. He resigned as leader soon after the election, and retired from politics in 1982.