Brimmer began to show his skills at the Rowville Sports Academy and with his junior club Nunawading City before joining the FFV NTC program.[4] Continuing to impress, Brimmer was in talks of a contract with Melbourne Victory before being spotted by Liverpool scout Barry Hunter, and subsequently signed a three-year deal for his childhood team.[5] On 10 June 2017, he was released by Liverpool.[6]
On 31 July 2017, Brimmer returned to Australia, joining A-League side Perth Glory.[7] In October 2020, Brimmer left Perth Glory for family reasons.[8]
In his debut season with the Victory, Brimmer made 25 appearances, finishing with 5 goals and 5 assists; alongside Rudy Gestede and Elvis Kamsoba, Brimmer finished as Melbourne Victory's joint top goalscorer for the 2020–21 season.[10]
Brimmer has been described as an all-action midfielder who is capable of scoring goals, and has a good habit of being in the right place at the right time.[15] He has also been described as having a great passing range and technical ability.[16]
Brimmer is of Maltese and Scottish ancestry.[22][23] Brimmer has two daughters.[24] Brimmer is currently in a relationship with Physio, Amelia Thomas[25]