[2] In early counting, just over an hour after the close of polls, the Australian Broadcasting Corporation's election analyst Antony Green predicted Phelps would win the by-election.

[1] The by-election came after Scott Morrison replaced Turnbull as Liberal leader and prime minister on 24 August 2018, following the second of two Liberal leadership ballots held that month, which saw Morrison win the ballot against Peter Dutton with 45 votes to 40 after third-placed Julie Bishop was eliminated and the 11 votes she achieved were re-cast in the final two-candidate run-off.

[5] Turnbull's departure dropped the Liberal-National Coalition in to minority government, with Nationals MP Kevin Hogan having declared he would move to the crossbench in protest immediately following the second spill.

[1][9] Other candidates for preselection included: Peter King, barrister and Turnbull's predecessor in Wentworth; Mary-Lou Jarvis, Woollahra councillor; Richard Shields, Woollahra councillor; Katherine O'Regan, Sydney East Business Chamber chair; Michael Feneley, cardiologist; Carrington Brigham, digital campaign business director; and Maxine Szramka, rheumatologist.

[1][10] Christine Forster, City of Sydney councillor and the sister of former Prime Minister Tony Abbott, announced her intention to seek preselection but then withdrew.

[15] From New York, Turnbull lobbied his former colleagues to refer his leadership rival Peter Dutton to the High Court over his eligibility to sit in Parliament and tweeting "The point I have made to @ScottMorrisonMP and other colleagues is that given the uncertainty around Peter Dutton's eligibility, acknowledged by the Solicitor General, he should be referred to the High Court, as Barnaby was, to clarify the matter.

They hoped that their candidate, Tim Murray, would secure third place in the election, and that ALP preferences would then be redirected to Phelps to increase her chances of winning the seat.

[30] In the last week of the campaign, an email was sent to hundreds of Wentworth constituents which falsely reported that Phelps was withdrawing from the by-election due to being diagnosed with HIV.

The email then encouraged the recipient to give their first preference vote to the Liberal candidate Sharma and to remove Phelps' campaign posters.

[41] Election analyst Antony Green partially attributed the size of the swing to the loss of Turnbull's significant personal vote.

[42] On 16 October, it was reported that the Liberal party's internal polling showed data that represented a 55% Phelps to 45% Sharma two-candidate-preferred vote result.

[6] The by-election is credited with highlighting the health concerns for refugee children detained in Nauru to the Morrison government's attention, and subsequently transporting some of them to Australia for medical treatment.