Born at Dreghorn in Ayrshire where his father was parish minister, William Allan Jamieson was educated at Irvine Academy. After attending arts classes at Glasgow University he emigrated to Queensland, Australia, to join relatives on a sheep farm. He graduated in medicine at Edinburgh in 1863, first man of his year. For nine years he engaged in general practice at Berwick-on-Tweed, then returned to Edinburgh and commenced practice in Rutland Street. Some years later, on the advice of Dr Douglas Maclagan and Dr Argyll Robertson, Allan Jamieson went to Vienna to study dermatology under Hebra. As a physician at the Royal Public Dispensary, he developed his interest in skin diseases and had the satisfaction of being appointed Extraordinary Physician in Diseases of the Skin to the Royal Infirmary, Edinburgh, in 1884.