[5] Brennan has also worked extensively in both the Queensland and Sydney theatre companies respectively, these credits include a self-written one woman show called 'Dangerous When Wet' as well and in the 60s spoof group The Harlettes during their Australian Tour.

on the Australian Tour during its run in 2001, Room To Move, Camille, Rosy Apples Too Darn Hot, Macquarie, Beach Blanket Tempest, Silhouette and many more.

In 2018, Brennan was rewarded for her efforts with a Voice Over Award or 'VoVo' for 'Most Emotionally Powerful Delivery' for the Peter MacCullum Cancer Centre ad 'Prevent, Detect, Act'.

[13] Brennan was announced in 2008 as part of the cast for ABC political comedy series The Hollowmen in the role of press secretary Mel.

Task Force Petra was introduced to investigate the murders, but was disbanded in 2011, the case however still remains open and unsolved and the $1 million reward for information still stands to this day.

[19]Brennan played prison officer Linda 'Smiles' Miles,[20] her first appearance was in season 1 episode 2 and had been part of the supporting cast for the shows entire run.

[18] Brennan would appear alongside several Wentworth cast members at a Screen Star Event in London and Birmingham in mid-2022 [22] and she would also appear alongside several cast members at Wentworth Con Melbourne in 2022, after withdrawing from the con's New Jersey event due to illness.

[28] The trailer for the telemovie also attracted negative commentary across social media when it was first shown on 31 May 2023 during the NRL State of Origin halftime break.