Johnstone, O’Shannessy & Co was founded in Melbourne in 1864 by Henry James Johnstone and a photographer known as ‘Miss O’Shaughnessy’, who had previously been in partnership with her mother in their own photographic business in Carlton. The firm exhibited photographs at the Intercolonial Exhibition in Melbourne in 1866, where the ‘special excellence’ of their work was noted by the judges. By the mid-1880s, when the firm moved from their Bourke Street address to purpose-built premises in the section of Collins Street known as ‘the Block’, Johnstone, O’Shannessy & Co. were arguably Melbourne’s leading portrait photographers, their services sought by governors, visiting royalty, politicians and other prominent members of society. Examples of Johnstone, O’Shannessy & Co.’s portraits were included in the Philadelphia Centennial Exhibition of 1875 and the 1888 Melbourne International Exhibition. They expanded to Sydney during the 1880s, but the firm’s fortunes declined during the economic downturn of the following decade.