The 1939 Hawthorn state by-election was held on 10 June 1939 following the death of incumbent MP John Gray. Gray, a United Australia Party (UAP) member, had died the previous month on 6 May. Despite a 34% swing away from the UAP (two Independent UAP candidates were also contesting), Les Tyack won the seat at the by-election for the UAP.[5]
The 1930 Hawthorn state by-election was held on 27 September 1930 following the resignation of incumbent MP William Murray McPherson. McPherson, who was Premier of Victoria from November 1928 until December 1929, had been defeated in a vote of no confidence following the 1929 state election. In August 1930, he announced his resignation as Nationalist Party leader and from politics.[7]