[4] Simmonds was elected to Brisbane City Council at a by-election in 2010, representing Walter Taylor Ward for the LNP.
Simmonds served as chair of the committees for public and active transport (2011–2012), finance, economic development and administration (2012–2016), and city planning (2016–2018).
In his final speech to council in March 2019 he recalled there were "not many jobs that would give a 26-year-old the chance to help manage a $3 billion dollar budget".
[6] In May 2018, Simmonds defeated the sitting member Jane Prentice for LNP preselection in the Division of Ryan.
[10] Simmonds lost his seat in the Division of Ryan during the 2022 federal election to the Australian Greens candidate Elizabeth Watson-Brown with a 10% negative swing against him.