Biddle was born in 1937. He was educated at Merchant Taylor’s School in Hertforshire, before he matriculated at Pembroke in 1958. There, he received a BA, eventually upgraded to a Cambridge MA. He is currently Professor Emeritus of Medieval Archaeology, Emeritus Fellow, Hertford College, at the University of Oxford, a position he has held since 2002. He is also an Honourary Fellow of Pembroke College, Cambridge. In 1997 he was awarded an OBE for services to the Royal Commission on the Historical Monuments of England, and was promoted to CBE in 2014 for services to archaeology.