He took priests' orders and appears to have held the chaplaincy of St Matthews, Dundee, but in March 1539 he was accused of heresy, apparently for having, in conjunction with his brothers, written some anti-Catholic ballads.
He became tutor to the son of Sir William Hickes, and was eventually glad to accept the patronage of William Pierrepont, earl of Kingston, whose kindly offer of a chaplaincy he had refused earlier.
Wished to appoint him canon of Windsor, but the prime minister, Lord Liverpool, objected; Sumner received instead a royal chaplaincy and librarianship, and other preferments quickly followed, till in 1826 he was consecrated bishop of Llandaff and in 1827 bishop of Winchester.
In October 189 9 he resigned his chaplaincy for reasons of health, and settled at Bellevue, somewhat farther away from Paris.
In some cases a parish priest is also appointed to a chaplaincy, but in so far as he is a chaplain he has no parochial duties.