This Manning was educated at Stowmarket and admitted as a sizar of Christ's College, Cambridge, on 25 October 1649, aged 16, with Henry More as his tutor.
He was one of three brothers, all holding benefices till the Act of Uniformity 1662, and members, while beneficed, of congregational churches; John (died 1694), who entered Emmanuel College, Cambridge, in 1633, and graduated M.A.
William was perpetual curate of Middleton, Suffolk, and ejected for nonconformity by the Act of Uniformity 1662.
According to Gordon[2] Manning seems to be the only instance of a Congregational minister ejected by the Act of Uniformity 1662 who later adopted fully Anti-Trinitarian views.
[3][4] Manning then looked for converts with some success, carrying a large part of his Peasenhall congregation with him, but failing with John Hurrion, at that time a student for the ministry (1698) at Heveningham, near Walpole.