Initially, and for many years after 1921, the Association was headed by Mr Harold Simpson out of his offices at Balmain Hospital.

The Association provided assistance public hospitals regarding industrial relations (the Association was industrial bodies representing public hospitals as employers) and legal issues (as these hospitals were independently run by volunteers the legal issues primarily involved resolving conflicts with hospital subscribers).

Notwithstanding these activities, the Association was responsible for the formation of the Hospitals Contribution Fund (now HCF Australia) in 1932. This was so patients could attend public hospitals. The Association is still a member of HCF Australia.

On 21 June 1991 the Health Services Association of NSW was incorporated replacing the old Hospitals' Association of NSW. This change was due in part to the centralisation of public hospitals into the NSW Department of Health which meant the employer representation function of the Association was no longer needed.

Although the Health Services Association of NSW is no longer registered as an employer organisation, it still actively lobbies the Commonwealth and NSW Governments on issues affecting the operating environment of public health service providers.