In 2018, Hickey successfully ran as a Liberal candidate for Denison (now Clark) in the Tasmanian House of Assembly.
[9] She unexpectedly won the Speaker position with the support of the opposition Labor and Greens parties over Liberal nominee Rene Hidding, and has stated that she will not attend Liberal Party meetings and will "mostly" vote with the Government, but will assess bills "on their merit".
[2][3] On 1 May 2018, at the first sitting of the House of Assembly after the election, Labor leader Rebecca White nominated Hickey as Speaker, in competition with the Liberal Party's preferred candidate, Rene Hidding.
Her vote was critical in several parliamentary votes opposed by the sitting government, most notably in advancing transgender-related birth certificate reforms and blocking legislation that would have made imposed mandatory sentences for serious child sexual assaults; citing "significant concerns from the legal profession" and "unintended consequences to the detriment of the victims".
Two days after quitting the Liberal Party, Hickey accused Liberal Senator Eric Abetz in the Tasmanian Parliament of making "slut-shaming" comments on Brittany Higgins, who was allegedly raped by a male staffer in the Federal Parliament in Canberra.
She alleged that Abetz told her at a citizenship ceremony in Hobart on March 1:As for that Higgins girl, anybody so disgustingly drunk who would sleep with anybody could have slept with one of our spies and put the security of the nation at risk.
Abetz "categorically denied" making the comments and accused Hickey of "trying to destroy the [Liberal] party".