Alexander Tweedie (1794–1884) worked as a house surgeon at Edinburgh Royal Infirmary before moving to become physician at the London Fever Hospital where he stayed for 38 years. In 1836 he was elected physician to the Foundling Hospital. Tweedie became a fellow of both the Royal College of Physicians and the Royal Society in 1838. It appeared strange to Tweedie that although French and German physicians had by joint labour brought out dictionaries, no similar work had been attempted in Britain. He accordingly planned and edited 'The Cyclopoedia of Practical Medicine' and eight volumes of 'The Library of Medicine'. Tweedie practiced medicine until the age of 89.

Little is known about the painter of this portrait, which was presented to the Royal College of Physicians by the sitter’s widow.