Born in 1935, John Oliver was educated at Westminster and Gonville and Caius College, Cambridge. He has Master of Arts (MA Cantab) and Master of Letters (MLitt) degrees.
He was made a deacon in 1964 at Cromer Parish Church and ordained a priest the Michaelmas following at Norwich Cathedral, both times by Launcelot Fleming, Bishop of Norwich. After a curacy in Norfolk, he spent a period as chaplain and assistant master at Eton College. Following incumbencies in Devon, he became Archdeacon of Sherborne and Rector of West Stafford in Dorset before being consecrated as a bishop on 6 December 1990 at Westminster Abbey. He served in the House of Lords from January 1997 until November 2003 with special responsibility for agricultural and environmental policy.