In 1961, he married Valerie Joy Prowse, with whom he had one son and two daughters. Prior to embarking on his academic career at the University of Western Australia (UWA) in 1969, he had worked as a press and radio journalist for four years and gained eight years' experience of teaching in primary, secondary and senior technical education. At UWA, he became an associate professor in political science "with a particular focus on twentieth century totalitarianism and was best known publicly for his involvement in two high-profile campaigns, as a leading critic of the Western Australian Burke Labor government ... and as a vocal direct-election republican". After his death, UWA established a Patrick O'Brien Foundation "in honour of his outstanding contribution to issues of public policy and political debate in Australia" with funds donated by colleagues, friends and admirers.
