However, it would be back to The Gorbals that he would return in 1874 to Mary Docherty and by then be playing the then brand new game of football and at the highest level. He had begun with Eastern on Glasgow Green, then is said to have turned for Jamestown in the Vale of Leven before joining Clydesdale back in South Glasgow at Kinning Park. And it was with it that he appeared in and lost the March 1874 Cup Final., the first ever. Furthermore, it was still as a Clydesdale player that in 1876 he both won the first of his two caps, both against Wales, probably as the first Catholic to play for the national team, and was a reserve against England, all between two visits to Sheffield; in February it was a part of Glasgow eleven to play a Sheffield one, in March it was with Clydesdale against Wednesday. And the following season, 1876-7,  it was Wednesday that he joined, said to have found been work in the cutlery factory of one the clubs directors. 

It does not mean that Lang was the World's first professional footballer. That accolade probably belongs to Jack Hunter, a local boy, who was playing for Sheffield rivals, Heeley, but he was the first Scot, or one of two Scots with Peter Andrews, to go South for money, although still not to play the Association game. Sheffield's teams played their own code. 

The stay in Yorkshire initially lasted a year. For the following season he was back in Glasgow's Southside once more, this time with Third Lanark, with which on 30th March he lost the 1878 Cup Final having just a week earlier won his second cap. But still with Thirds after already being knocked out the next season in the Cup's fourth Round once more he was on the move. For the next three campaigns he was back at Wednesday and now bringing his family with him. His and Mary's first two children had been born in Glasgow in 1878, the third was born in Sheffield in 1881.       

However, by 1882 he was home again. For the 1882-83 season he was again with Third Lanark before now at the age of thirty-one he went freelance. He had been tempted South as a trainer, the family seemingly staying put, and also for the next two seasons played for a number of teams on a match-by-match basis. That is before in 1886 returning to his home-city once more, back to his old trade once more and to train the Cathkin Park team. Two more daughters had been born in Glasgow in 1883 and 1885 as was a second son in 1888. 

However, Mary would die in 1892 at the age of just forty. And James would remain a widower until his death Stobshill Hospital in 1929, staying in The Gorbals until about 1900, moving first to Anderston and then by his death to the city's north-western suburbs.