[5] Carter's middle name probably derives from the time his father spent as domestic chaplain to John Thellusson, 2nd Baron Rendlesham.

Carter was ordained a priest by John Kaye, Bishop of Lincoln, on 22 December 1833 and went to serve as his father's curate, who was now vicar of Burnham, Buckinghamshire.

Within the large parish, a particularly poor area was the slum of Clewer Fields, which contained two army barracks and a swiftly changing population of railway navvies, which served to worsen the general problems of drink, prostitution and poverty.

Ill-health prompted Tennant's withdrawal from the project in 1851, and she was succeeded by another widow, 40-year-old Harriet Monsell, who became mother superior of the newly created Community of St John Baptist, Clewer on 30 November 1852.

[5] Carter was also one of the key figures in the founding of another order of religious sisters, the Community of Reparation to Jesus in the Blessed Sacrament (CRJBS).

Carter's involvement in the establishment of this community, and his general commitment to pastoral work drew him into the provision of spiritual direction, which became a new focus of activity and led to the book, The Treasury of Devotion which appeared in 1869.

[5] Carter was married at Amberd, Taunton, Somerset on 26 November 1835 to Mary Ann Gould (1802 – 7 February 1869), with issue including: