During his time in the United Kingdom, he paid £6 to become a life member of the Cambridge University Conservative Association.

[11] Speakman had challenged Mutch for the Cook preselection prior to the 1998 federal election, but withdrew from the contest when former state deputy Liberal leader, Bruce Baird, became the compromise candidate.

[16][17][18] The First Berejiklian ministry was subsequently formed with Speakman sworn in as the Attorney General of NSW with effect from 30 January 2017.

[5] Following the 2019 state election Speakman was appointed as the Minister for the Prevention of Domestic Violence in addition to his responsibilities as NSW Attorney General in the second Berejiklian ministry with effect from 2 April 2019;[19] a title subsequently amended as the Minister for Prevention of Domestic and Sexual Violence in May 2021.

On 9 June 2023, Speakman was granted retention of The Honourable title by the Governor for life, for having served as a Member of the Executive Council for more than three years.