William Crawford Kemsley of Port Elizabeth was the son of John Chambers Kemsley and his wife Martha, born Crawford. In 1874 he joined his brother in the firm James Kemsley and Co., publishers of the Port Elizabeth Telegraph. The paper was renamed The Cape Daily Telegraph in 1898 and the firm was closed after a fire in 1908. He was married to Susanna Elizabeth, born Frost. After her death in December 1913 he married Johanna Kessia. Altogether he had eleven children, including a son named William Crawford like his father.
In 1883 Kemsley was the auditor of the Port Elizabeth Naturalists' Society (1882-1884, then renamed the Eastern Province Naturalists' Society). He was not a member of the society at that time, but was elected as a member in May 1887.
By 1895 he was an active plant collector and was making a vigorous attempt to collect all the flowering plants in the Port Elizabeth area. Duplicates were sent to the herbarium of the Albany Museum in Grahamstown. Ten years later his interests included the collection of fish, of which he donated 14 specimens to the Port Elizabeth Museum in 1905.
In 1913 he published a pamphlet, A short sketch of the Port Elizabeth Royal Arch Chapter, no. 711, 1864-1913 in Cape Town.