Brian Johns spent his early life in Queensland and moved to Sydney in 1947 with his family, father Frank, a waterside worker and barber, Irish-born mother Lenora and sister Daphne. Johns's father opened a barber's shop in Kings Cross and the young Johns worked a paper run and in factories before entering St Columba's seminary at sixteen years of age. He left the seminary three years later, moved to Canberra and worked as a journalist with the Queanbeyan Age, the Australian News and Information Bureau, and from 1964 (after a return to Sydney in 1962) as Chief Political Correspondent in Canberra for the Australian. During this time he wrote fiction, having some short stories published, wrote for the Nation and was editor of the Catholic magazine Prospect (1964). From the Australian he moved to the Bulletin and subsequently he joined the Sydney Morning Herald.
In 1974 Johns joined the Department of Prime Minister and Cabinet as First Assistant Secretary and Principal Adviser. In 1979 he was appointed Publishing Director of Penguin Books Australia and in November 1987 Managing Director of the Special Broadcasting Service, a position he held until joining the Australian Broadcasting Authority as Chair in 1992. He was Managing Director of the ABC (1995-2000) and Adjunct Professor in the Creative Industries Faculty at Queensland University of Technology (QUT). Throughout his career Johns also filled a number of important cultural positions including Chair, Australian Book Review, Council Member, National Gallery of Australia, Vice President, Asia-Pacific Broadcasting Union, Chair of Copyright Agency Limited (CAL) and Chair of QUT's Cultural Precinct.