[2] In 1960, Penny graduated with honours from Sydney Medical School, and undertook further study in haematology, oncology and immunology in Britain and the United States.
In 1967, he returned to Australia and began work at Sydney's Royal Prince Alfred Hospital, where he set up the first clinical immunology unit in New South Wales.
[3] In October 1982, Penny and his team at St Vincent's made the first diagnosis of HIV/AIDS in Australia, just over a year after the first clinical reporting of the disease in the United States.
[2] In 1983, Penny conducted a survey in New South Wales to better understand the connection between the spread of AIDS, sexual behaviour, and drug usage.
[3] In the 1993 Queen's Birthday Honours, Penny was made an Officer of the Order of Australia (AO) for "service to medical research and education particularly in the field of clinical immunology".