[1] In 1858 Overton was ordained to the curacy of Quedgeley, Gloucestershire, and in 1860 was presented by J. L. Fytche, a friend of his father, to the vicarage of Legbourne, Lincolnshire.
Overton was collated to a prebend in Lincoln Cathedral by Bishop Christopher Wordsworth in 1879, and in 1883, on William Gladstone's recommendation, was presented by the crown to the rectory of Epworth, Lincolnshire.
[1][2] Early in 1903 Carr Glyn, the bishop of Peterborough, made him a residentiary canon of his cathedral; he was installed on 12 February.
[1] Overton was for more than 20 years an Honorary Chaplain to the 1st Lincolnshire (Western Division) Artillery, for which he received the Volunteer Officers' Decoration (VD) 3 April 1894.
A stained-glass window [13 Nave - North Wall (ix)] in St James' Church, Louth, Lincolnshire has the dedication 'To the glory of God and in memory of John Henry Overton M.A.
[1] In 1878, with his college friend Charles John Abbey, rector of Checkendon, Oxfordshire, he published The English Church in the Eighteenth Century, 2 vols.
He also published:[1] At his death Overton left unfinished A History of the English Church from the Accession of George I to the End of the Eighteenth Century,’ a volume for the "History of the English Church" edited by Dean Stephens and William Hunt; the book was edited and completed by the Rev.