He was born in London to storekeeper John Barnes and Elizabeth Ellen King.
The family emigrated to New South Wales and settled at Little River, a small sheep station near Yass.
Young John attended Burwood Denominational School until the age of fourteen, when he went to the Turon River gold rush.
After trying unsuccessfully at Ophir and Abercrombie, he returned to Sydney to be apprenticed to a cabinet maker.
[1] In 1887 he retired from business and turned his attention to politics, winning election to the New South Wales Legislative Assembly in 1889 as the Protectionist member for Gundagai.