Walter H. Greathead was the eighth child of James H. Greathead, a member of the Legislative Council of the Cape Colony, and a younger brother of the eminent medical practitioner Dr J.B.S. Greathead*. He received his schooling at St Andrew's College, Grahamstown, and from 1874 to 1876 studied at the South African College in Cape Town, passing the matriculation examination of the University of the Cape of Good Hope in the latter year. During 1876 and 1877 one W. Greathead (either Walter or Wilson Greathead) was engaged as secretary to the Meteorological Commission of the Cape of Good Hope, with responsibility for the processing of the meteorological data and inspection of its network of meteorological stations. Meanwhile he continued his studies and in 1877 passed the examination for the Certificate of proficiency in the Theory of Land Surveying of the University of the Cape of Good Hope. The next year he was on active service in the Griqualand West rebellion and in 1879 was admitted to practice as a land surveyor in that territory. In July 1881 he was admitted to practice as a land surveyor in the Cape Colony and subsequently also in Rhodesia (now Zimbabwe, in March 1898) and in the Transvaal (February 1902).
From 1882 to 1885 Greathead was engaged in an engineering apprenticeship on the Great Eastern Railway in England and subsequently became an associate member of the (British) Institution of Civil Engineers. After returning to South Africa he resided in the Transvaal from 1887 to 1891. He was an accomplished sportsman and in 1889 played cricket for Transvaal against the first English cricket team to visit this country. In 1895 he married Rosa L. Candy and returned to England to join his brother J.H. Greathead, who was engaged in surveys for the Londen underground railways. From 1898 to 1901 he was in Zimbabwe and then settled in Johannesburg were he practised on his own as a civil engineer and government land surveyor. He remained there for the rest of his life.
In 1904, at the second annual meeting of the South African Association for the Advancement of Science which took place in Johannesburg, he delivered a paper on "Geodetic surveying". It was published in the association's Report for 1904 (pp. 402-410). He was a member of the association, and by 1906 had also joined the Geological Society of South Africa. He was survived by his wife and three children.