Lieutenant-Colonel George Johnston was a British military officer who served as Lieutenant-Governor of New South Wales, Australia after leading the rebellion later known as the Rum Rebellion. After serving as a young marine officer in the American Revolutionary War, Johnston served in the East Indies, fighting against the French, before volunteering to accompany the First Fleet to New South Wales. After serving as adjutant to Governor Arthur Phillip, Johnston served in the New South Wales Corps and he was a key figure in putting down the Castle Hill convict rebellion in 1804. He led his troops in deposing Governor Bligh in the Rum Rebellion in 1808; which led to his court martial and subsequent cashiering from military service. In his later life, he returned to New South Wales as a private citizen, raising a family in the colony and establishing a successful farm around Annandale in Sydney.

The Rum Rebellion of 1808 was a coup d'état in the then-British penal colony of New South Wales, staged by the New South Wales Corps in order to depose Governor William Bligh. Australia's first and only military coup, its name derives from the illicit rum trade of early Sydney, over which the 'Rum Corps', as it became known, maintained a monopoly. During the first half of the 19th century, it was widely referred to in Australia as the Great Rebellion.