Samuel Parlby was the son of Reverend Samuel Parlby. In 1804, at the age of about 15, he joined the Bengal Artillery in the Indian Army and two years later was present at the second British annexation of the Cape of Good Hope. From 1822 he was the editor of the newly created journal The British Indian Military Repository (Calcutta, 1822-1827, Vol. 1-5). He retired from military service in India in 1831 with the rank of major, and came to the Cape where he bought the Klein River Estate, some 20 km east of Hermanus. The village of Stanford later grew up around his residence. He was married three times, first to a Javanese woman (who died in 1816) with whom he had an only son, John S. Parlby, who farmed near Oudtshoorn; then at Cape Town in 1831 to Hester Vowe (1808-1835); and later at Rondebosch to Marian E. Mathew (who died in 1871).
As an imaginative and progressive farmer Parlby advocated more efficient methods of flax cultivation, experimented with various crops imported from England and India, and made extensive use of irrigation. A leading breeder of merino sheep, he experimented with cross-breeding to improve his stock. Some of his agricultural proposals were made in letters to local newspapers. For example, in 1834, in a letter to the South African Commercial Advertiser, he answered objections against the cultivation of opium poppies at the Cape and declared his intention of growing them for the oil which can be pressed from the seeds.
As a strong supporter of British immigration to the Cape he published a pamphlet, Hints to emigrants, in which the climate, capabilities, and geographical position of the British colony of the Cape of Good Hope are submitted for examination and consideration (London, 1838, 23 pp). The booklet contained a table of daily meteorological observations (air temperature, wind direction and speed, and weather conditions) for January 1834 to August 1835 at his estate. In 1839 he moved to Green Point, Cape Town, where he continued his meteorological observations. His measurements of rainfall during the period June 1839 to February 1840, with some observations about temperatures, were published in the South African Commercial Advertiser. He was particularly impressed with the mild climate of Green Point compared to the rest of Cape Town.
Parlby was a member of both the Swellendam Agricultural Society (founded in 1832) and the Agricultural Society of the Cape of Good Hope (founded in 1831). In a letter of 7 March 1840 to the newspaper he announced that he had sold his property in Green Point and would move away on or before 5 June that year. By 1843 he was living in Paris and published a paper in the Transactions of the Society for the Encouragement of Arts, Manufactures and Commerce (London, 1843-1844) entitled "Floating breakwater". The society awarded him its silver medal for this work. He appears to have returned to England around 1850.