 In March 1804 he acted with decision when in command of the military sent against some convicts who had rebelled at Castle Hill.When Paterson was sent to Port Dalrymple, Johnston became commander of the New South Wales Corps.On 26 January 1808, Johnston played a key role in the only successful armed takeover of a government in Australia's recorded history, the Rum Rebellion, working closely with John Macarthur.