William John Atherstone was educated in Grahamstown and London. He matriculated through the University of the Cape of Good Hope in 1889, and two years later passed the university's examination for the certificate of proficiency in the Theory of Land Surveying. He worked as a surveyor in the Transvaal from 1892 to 1894, was admitted as a land surveyor in the Cape Colony in 1895, and worked as a surveyor in that colony from 1895 to 1898. In the latter year he married Annie L. Dallas, with whom he had two children.
In July 1898 Atherstone joined the Surveyor-General's office in Salisbury, Rhodesia (now Harare, Zimbabwe) as surveyor to the British South Africa Company. He became assistant examiner of diagrams in that office in May 1901, and Surveyor-General of Rhodesia in December 1903. In March 1904 he attended the geodetic congress in Cape Town, where the surveyor-generals of southern Africa and Sir David Gill*, Her Majesty's astronomer at the Cape, planned the further geodetic survey of the sub-continent. He was still Surveyor-General in 1923, but by 1927 was director of the Department of Lands of Rhodesia, stationed in Salisbury. He became a member of the Rhodesia Scientific Association in 1924.