Prior to joining the CSU in 2021, Brett was a NSW Police officer for 32 years performing a variety of duties both in uniform and plain clothes attaining the rank of Sergeant. Brett was attached to several Police Commands mainly in Metropolitan Sydney where he performed General Duties, Proactive Crime Team duties, Licensing, Intelligence, and Counter Terrorism - Dignitary Protection Duties.

Prior to retiring from the NSW Police in 2020, Brett was a Lecturer at the NSW Police Academy for several years teaching a broad range of subjects including Law, Investigations, Communications and Ethics.