Educated at the Mercers' School, D'Aeth started work as a clerk at the National Assurance Company aged 15, where his apprenticeship allowed him to learn business administration and bookkeeping.
[4] Having left Oxford, later that year D'Aeth was ordained a deacon, and admitted in that role to Manchester Cathedral, working also as curate of St Matthew's Church, Habergham Eaves, Burnley, Lancashire.
The duties of the clergy here primarily related to relief of poverty; D'Aeth was dismayed by the scale of the deprivation experienced by the local people.
[8] By 1905, disillusioned by the church's attitude to poverty, D'Aeth (at the same time as his vicar) abandoned his clerical career, taking an appointment as junior lecturer at Liverpool University.
[13][14] D'Aeth and his wife Margaret had two sons: Christopher John (1910–1931), who after Rugby and Balliol College, Oxford (where he read chemistry) died of exposure during a snowstorm whilst serving as ornithologist on a ten-man expedition to the uninhabited island of Akpotek, beyond Labrador in the Hudson Strait; and Andrew Maynard (b.