[citation needed] Appointments have included Bampton Research Fellow, St Peter's College, Oxford; Dean, Chaplain, Fellow and Director of Studies in Philosophy and Theology, Peterhouse, Cambridge; and FD Maurice Professor of Moral and Social Theology, King's College, London.
He has been chairman of HM Government Committee of Enquiry on the Ethics of Emerging Technologies in Breeding Farm Animals and the CJD Incidents Panel, Department of Health.
In 2022 Banner publicly defended the views of a post-doctoral junior named Joshua Heath, a Junior Research Fellow of Trinity College, Cambridge, who had preached a sermon in the College chapel in which he (not Banner) had suggested that the wounds of Jesus had a "vaginal appearance" and that the body of Christ "is also the trans body."
He reimagined the story of Catherine of Siena drinking from Christ's wound as an erotic experience in which her thirst is "slaked" on the crucified Lord.
Banner was quoted in the Times as saying the preacher's views were a "legitimate" treatment of medieval artistic representations of the crucifixion and that his own response was then “grossly misrepresented”.