Samuel Middleton Gannon was born in Sydney on 5 December 1857, second son of John Thomas Gannon and his wife Harriette (née Jones). As a youth he absconded from the family home at Goulburn, but later returned there where he set up in business and married. The business failed within a very short time, and his marriage some little time later. His education had seemingly equipped him for clerical work, but he never managed to hold down a job for very long. He did, however, prove to be a career petty criminal, and he spent a considerable time in various gaols, both in New South Wales and later in New Zealand, where he died, a lonely old man, in 1915.