Francis Johnston was born around 1760 in Northern Ireland. In 1778 Johnston studied architecture under Richard Robinson in Dublin. In 1794 he designed Townley Hall, county Louth. Johnston also built the infirmary of the Foundling Hospital, James Street (1810), the castle chapel (1807–16), the Richmond General Penitentiary (1812–20), alterations in the Bermingham Tower, Dublin Castle (1813) and the General Post Office (1815–17). Johnston died on 14 March 1829 in Dublin.