Kelly was born in 1865 in Renton. He was another son, the eldest son of twelve siblings, of irish immigrants, both born in Co. Antrim, his father a Shipyard Labourer/Hammerman. In 1881 the family was living on Thimble St. in the village, at the time probably the most footbal wynd in the World. James was working as a joiner. A decade later he was living in Camlachie in Glasgow, at the house of his father-in-law, having married Donegal-born Maggie McErlean, daughter of another Celtic-founder, early that same year. Now he is listed as a Spirit Merchant, actually a pub-owner and the profession he would pursue until his death. But, of course, by then he had already played for Renton from 1883, aged eighteen, initially as an inside-forward, had been in the Scottish Cup winning-team in 1885, still at inside right, won a cap in 1886, repeated the Cup win in 1888, won a second cap and been in the Renton team which that same year had taken the "World Championship" in beating West Bromwich Albion. 

It was these performances that saw him still in 1888 recruited to be captain by the newly-formed Celtic and the move to the East End of Glasgow. But he had won the last two trophies and cap in the novel position of centre-half, but the attacking, Scottish centre-half that he had already made his own and would continue to play until 1897 and the end of his footballing career. It would bring him a further seven caps, a further Scottish Cup win and three League titles.