Pettingall was born in Newport, Monmouthshire, Wales He attended Cowbridge School and there even learnt some Hebrew before matriculating from Jesus College, Oxford in 1725. He obtained his B.A. degree in 1728 and moved to Corpus Christi College, Cambridge, receiving his M.A. degree from there in 1740. He was later awarded the Lambeth degree of D.D.. He was ordained at Llandaff Cathedral in 1732 and, after serving as chaplain to the Bishop of Llandaff, he was rector of Whitson and vicar of Christchurch, both near Newport, Wales. He held these positions until 1756. Thereafter he was appointed rector of Stoke Hammond, Buckinghamshire, a position that he held until his death in Stoke Hammond in 1781.
- Iolo Davies, A Certaine Schoole, pp 29-30 (Cowbridge 1967).
- "Pettingall, John (PTNL740J)". A Cambridge Alumni Database. University of Cambridge.
- Norgate, G. Le G.; Mercer, M. J. (2004). "Pettingall, John (1707/8–1781)". Oxford Dictionary of National Biography (online edition). Oxford University Press. Retrieved 2008-02-25. (Subscription required (. ))