Career
In a long professional career, he played for nine clubs, Arbroath, Ross County, Dundee, Rotherham, Peterborough, Cambridge, Fulham, Millwall and Montrose. He managed Arbroath for four years before resigning in October 2009. In summer 2005 McGlashan returned to Dundee Violet as player–manager.
His father, also John, had been captain of Dundee Violet.
That September Harry Cairney resigned as Arbroath manager and McGlashan was appointed as his replacement. The following month McGlashan made himself his first signing, re–registering as a player despite missing most of the previous season with a back injury.
He made a further two league appearances for the club, over the next two seasons. McGlashan had a spell as manager of Millwall Lionesses during his time in London.