From the University of Sydney Gordon Ada received a BSc in 1943, an MSc in 1946 and a DSc in 1959. His first research position was at the Commonwealth Serum Laboratories (CSL) from 1944 to 1946, where he worked on ridding blood serum of precipitates. The realisation that he needed to get further experience and learn new techniques led to him moving to London to work at the National Institute for Medical Research. Working there from 1946 to 1948, he mastered moving boundary electrophoresis and ultracentrifugation, which were then new biophysical techniques used for the study of proteins.

While in London he was invited to join the staff of Melbourne's Walter and Eliza Hall Institute for Medical Research (WEHI), by the then Director Frank Macfarlane Burnet, to help establish the Biochemistry and Biophysics Research Unit with Henry Holden. He accepted the invitation and stayed at WEHI from 1948 until 1968. During this time he became first a virologist and then an immunologist. As a virologist he studied the influenza virus and the Murray Valley encephalitis virus. In 1962 Ada changed to immunology and began his study of the nature and location of cells that bind antigen. Over the next six years they studied the role of antibody in antigen localisation and demonstrated the absence of antigen in antibody-forming cells.

Ada left WEHI in 1968 to become Head of the Department of Microbiology at the John Curtin School of Medical Research, Australian National University, a position he held until his retirement in 1988. Under his leadership the department combined virological and immunological approaches, becoming an international centre for the study of cellular immune response. In his department during this time were Peter Doherty and Rolf Zinkernagel, conducting the research that led to their being awarded the 1996 Nobel Prize for Medicine or Physiology.

In 1971, shortly after arriving in Canberra, Ada became interested in international health through his association with the World Health Organization. This involvement lasted more than 20 years and covered eight different programs, most being concerned with the development and use of vaccines.

During 1988-1991 Ada was at the Johns Hopkins School of Hygiene and Public Health in Baltimore, USA. As director of the School's Center for AIDS Research. In 1988 he delivered the plenary lecture on The prospects for HIV vaccines to the Fourth International AIDS Congress in Stockholm. In 1991 he returned to Canberra as a Visiting Fellow in the Division of Immunology and Cell Biology at the John Curtin School.

Ada was elected a Fellow of the Australian Academy of Science in 1964 and has served the Academy in a number of roles. He has also served as President of the Australian Biochemical Society (1966-67) and the Australian Society for Immunology (1975-76). In 2001 he was honoured by induction into the Johns Hopkins Society of Scholars.
Biography taken from the listed Australian Academy of Science on-line resource.