Dr Bradstock is co-director of the Centre for Faith in Society at the Von Hugel Institute at the University of Cambridge, England.
As well as undertaking research and teaching, he will be responsible for establishing a new Centre for Theology and Public Issues at Otago University.
The new professorship was established as a result of a major gift by the Paterson Charitable Trust.
Mr Paterson was a successful Otago businessman who died unexpectedly in 2003.
An Otago graduate, Mr Paterson had studied the phenomenology of religion and retained a lifelong interest in the subject.
The Presbyterian Synod of Otago and Southland, and Southland couple Ian and Annette Tulloch, also provided substantial support for the professorship.
Because the gifts were made through the university's Leading Thinkers initiative, they were matched under the Government's Partnerships for Excellence scheme, bringing the total to $2.35 million.
Born in London, Dr Bradstock studied theology and politics at Bristol University, and completed a PhD in political theory at the University of Kent.
Later, he was a postdoctoral fellow in church history at Otago University (1990-91), also gaining an Otago master of theology degree.
He then returned to England, teaching theology in several institutions before becoming the secretary for church and society of the United Reformed Church (2000-05).
He has been director of the Christian Socialist Movement for the past four years.
Dr Bradstock was excited about the opportunities presented by the new job, which he will take up early next year.
Vice-chancellor Prof David Skegg said Dr Bradstock's writing combined historical scholarship with work that engaged directly with the interface between faith and public policy.
It was hoped the new centre would contribute to "an intellectually informed theological perspective on matters of public interest", Prof Skegg said.
Prof Paul Trebilco, who heads the Otago theology and religious studies department, said there was widespread enthusiasm about the new centre and it was wonderful Dr Bradstock was taking up the professorship.
