Born in Kent, England, on 4 August 1837 and died at Leura, N.S.W., on 3 August 1919.
He arrived in Australia in 1856 and took a position on Cassilis Station in Queensland, but later became a partner in Mount Rainsworth Station and managed it for 12 years. In 1875 he became Assistant Superintendent and shortly afterwards Superintendent of the Australian Agricultural Company, holding the latter position until 1905.
Shortly after Gregson was appointed to the position of Superintendent (1876), he bought a small holiday property at Mt Wilson, in the Blue Mountains area of New South Wales. He had been keenly interested in botany from the time of his arrival in Australia and made a detailed and careful collection of plants, especially in the Mt Wilson area, which has a rich basaltic soil and a high rainfall. He was particularly interested in eucalypts and the specimens he collected were sent to the National Herbarium in Sydney. This led to a friendship with J. H. Maiden and to the latter accompanying Gregson on collecting excursions. All his botanical specimens are at the Herbarium.
He is honoured in the name Eucalyptus gregsoniana
L. Johnson & D. Blaxell (1973)
(jointly with his son, Edward Jesse)