Colleen was originally a minor character in her beginnings however her role starts growing after Meg Jackson leaves to become a parole officer. She was a Union Representative for the officers, and as her character fleshed out, she became very ambitious in this role, even sarcastic at times.
At one stage, Colleen started to replace Vera Bennett as the fair but firm screw, virtually taking over from Vera once she left she show.
Later on, Colleen tries for the position of Deputy Governor, competing with Meg Jackson for the job. Meg wins, but decides she doesn't even want the job, so Colleen becomes the new Deputy Governor by default. Colleen becomes nice as the show goes on, most notably when prisoner Susie Driscoll arrived at Wentworth, and when Joan Ferguson arrives as an officer. She still adhered to the rules, but she became a bit more fair-minded and compassionate, yet maintaining her sardonic and sarcastic sense of humour which earned her the nickname, Po-Face.
Colleen's family are later blown up by a car bomb (433). The car was owned by another officer, Rick Manning, and the bomb was placed to target him. She sold her home as it was too full of memories, then resigned from Wentworth to take an extended cruise around the world. On her last day at Wentworth Colleen almost didn't make it out when she was taken hostage by crazed Nazi Peter Secker who was really after Hannah Geldschmidt.