Ms Hillier commenced her legal career in London, UK in 2007. In 2009, and after completing her training contract in London with a global law firm, she qualified as a solicitor in England & Wales.
As a trainee solicitor and then solicitor, she acted for insurers (and insureds) in the areas of medical negligence, coronial inquests and inquiries (including matters for the NHS Litigation Authority), professional indemnity (solicitors, accountants, architects, engineers, surveyors, and veterinary surgeons), equestrian and bloodstock, and product liability including recalls. She also provided coverage advice to insurers and re-insurers:
Mopani Copper Mines plc v Millennium Underwriting Ltd  EWHC 1331 (Comm) (effect of deleting words in a placing slip).
Ms Hillier undertook the Lloyd’s of London Introductory Market Test (as it was then known), and completed several secondments with insurers including working within corporate insurance teams, claims teams, and with underwriters of a Lloyd’s syndicate.
In 2012, Ms Hillier was admitted as a lawyer in New South Wales, and continued to act for insurers and self-insureds in the areas of medical negligence, professional indemnity, equestrian and bloodstock, and public and products liability. Ms Hillier has also acted for medical/health professionals subject to investigation and disciplinary action including s.150 proceedings.
Ms Hillier was called to the NSW Bar in 2017.
Ms Hillier has chambers in both Canberra and Sydney and is a member of both the NSW Bar Association and the ACT Bar Association.