Harry D'A. F. Harrison worked for the London and South Africa Exploration Company during the late 1890's. The company had been involved in diamond mining ventures in the Kimberley area from 1870. By 1895 he was a voluntary meteorological observer at Kimberley for the Cape of Good Hope Meteorological Commission, and that year was sent a maximum-minimum thermometer by the secretary. (In the commission's report for 1895 his initials were wrongly given as H.W.F.) He continued to supply observations in 1896 (when his initials were wrongly given as W.H.F.) From 1897 (his initials finally correct) his station was upgraded to a second order meteorological station, and by 1899 he also measured evaporation. However, he left Kimberley in the beginning of August that year. His observations for the commission ended in July 1899 and the station was discontinued.
From 1900 to 1902 Harrison studied at the South African College, Cape Town, and in the latter year passed the Survey Certificate examination of the University of the Cape of Good Hope. He was admitted to practice as a land surveyor in the Cape Colony in 1903 and that same year set up for business in Durban. Still in 1903 he was admitted to practice also in the Transvaal Colony. He moved to Potchefstroom, where he worked in the Land Settlement Offices by 1905, and became a member of the Institute of Land Surveyors of the Transvaal.
Harrison was married to Edith Mary Walker.