John Wallace Jackson worked as an assistant at the Royal Observatory, Cape of Good Hope, from 1903 to 1946. After private study he passed the examination in the Theory of Land Surveying of the University of the Cape of Good Hope in 1904. After 1926 he gradually took over the programme of observations with the Victoria telescope aimed at the photographic determination of stellar parallax that was conducted by H.S. Jones, His Majesty's Astronomer at the Cape from 1923 to 1933. John Wallace Jackson should not be confused with John Jackson, who succeeded H.S. Jones as H.M. Astronomer from 1933 to 1950. John Jackson continued the parallax work of his predecessor, presumably with the assistance of John Wallace Jackson, and published the results in the Annals of the Cape Observatory during 1935-1952.