John was a master draughts player and twice crossed swords with Robert Martins. Both matches took place in Glasgow: the first in 1858, for the championship of Scotland and England and £100, produced a drawn result, and the second in 1859, for £200, was won by Martins 10-6-36.
He was also highly valued as a match second; even the great Anderson used his services (see McKerrow's account of the Anderson - Wyllie matches in which he acted as second to Anderson). In between times we find him with his pal John Drummond hustling the poor English for money (see the article on John Drummond for more on this).
However the main legacy from McKerrow must be his wonderful letters to the Scottish Draughts Quarterly and Draughts World at the turn of the century. We can only marvel at the quality of these - remember that McKerrow was a working class man of no great education! See his account of the Anderson - Wyllie matches for an example.
John McKerrow died on the 12th of October 1910 aged 84 and is buried in the Old St Bride's Cemetery, Douglas, near to his old friend and opponent Robert Martins.