[1] In his maiden speech to parliament he stated that he had installed the passenger information system for the Perth Central Area Transit (CAT) bus network.

[4][5] O'Sullivan was the Liberal Party's candidate in Burt at the 2016 federal election, at which point he was living in Aubin Grove.

[7][5] In his first speech to parliament in July 2019, he argued for the extension of the Forrest-backed Cashless Welfare Card across Australia and for a major overhaul of the federal employment services system, including replacing unnecessary Jobactive appointments with online reporting.

[11][12] In November 2019, he became a member of a new cross-party parliamentary working group into indigenous constitutional recognition and a "voice to government".

[16][17] O'Sullivan and his wife Montanique live in the southern suburbs of Perth, where they raise their two children Amy and Samuel.