John F. Gavin was born in Sydney on 9 February 1874, the eldest child of Francis Gavin and Catherine (née O'Brien).Family records, Ancestry.com. Gavin later claimed he worked for a circus as a ten year-old. He moved to the country and worked as a cattle drover, being involved in a record cattle drive from Camooweal in Queensland to Adelaide. "A man of fine physique and imposing presence" he served for a time in the Sydney Lancers as the captain of a squadron. He was interested in acting and received an offer to join the touring company of Bland Holt. He stayed with them for a number of seasons, then travelled to the USA where he worked with Barnum and Bailey's Circus, and Buffalo Bill's Wild West Show. He married Agnes in 1898.
