Career
Johnston was attached to Rangers Football Club, Cowdenbeath and Raith Rovers as a youth player before his family emigrated to Australia when he was aged fourteen, where he played for Perth Glory. Returning to Scotland in November 2011, he joined Dundee United on a short term contract in January 2012 and went on to make a number of appearances for the club"s under-19 team He signed a new contract in the close season of 2012 and began to feature in the first team squad towards the end of the campaign.
Johnston made his first team debut as a substitute against Ross County in April 2013, and also played from the start in the next match against Street Johnstone.
He spent the next season on loan at Dunfermline Athletic and Montrose, but then left Dundee United at the end of the season following the expiry of his contract.