Catherine Pirie graduated from the Queensland University of Technology with a Bachelor of Laws in 1988, and the following year undertook a Post-Graduate Diploma in Legal Practice. While completing her studies, Catherine was employed as a Law Clerk with Messrs Paul Richards and Associates, a firm of solicitors retained to act for the Aboriginal Legal Service in Brisbane.

In 1989, Catherine obtained full-time employment with Messrs Philip Mitaros, Barristers and Solititors in Darwin. Whilst in Darwin, she also undertook a short period of employment with the North Australian Legal Aid Service, allowing her to establish a rapport with a diverse range of communities in remote areas. In 1989,Catherine was admitted as a solicitor of the Supreme Court of Queensland, the first Torres Strait Islander woman to be admitted in Queensland. She then moved to Townsville to take up a position with the Aboriginal and Torres Strait Islander Legal Service as a Solicitor and Principal Solicitor. In 1993, Catherine was employed with the Aboriginal Legal Service of Western Australia, commencing her position in Northam prior to her transferal to the Albany regional office.

In her capacity as a Solicitor with the ALS, Catherine gained extensive experience as Counsel in complex and routine matters in Courts of all jurisdictions, as well as accepting high levels of personal responsibility for administration and supervision of staff. In 1999, Catherine accepted a position with the newly opened Community Legal Centre in Albany.

In September 2000, Catherine was appointed a Stipendiary Magistrate for the State of Queensland, the first female Torres Strait Islander to be appointed to this position.