Oliver Crace Penfold, eldest son of William Penfold and Clarissa Sophia Blunden, grew up in England. He qualified in London as a Licentiate in Dental Surgery (LDS) of the Royal College of Surgeons of England in 1898. Two years later he came to South Africa, was registered to practise in the Colony of the Cape of Good Hope on 15 October that year, and settled in Cape Town, where he practised until his retirement in 1940.
At first Penfold collected moths, but he soon changed to plants. He became a member of the Botanical Society of South Africa in 1919. His specimens went to the Compton Herbarium in Cape Town.