Born in Inverness, Armstrong attended Hazlehead Academy in Aberdeen, alongside fellow footballers and Inverness Caledonian Thistle before joining Dundee United in July 2009.
Born in Inverness, Armstrong attended Hazlehead Academy in Aberdeen, alongside fellow footballers Fraser Fyvie and Ryan Jack. Armstrong formerly played for Dyce Boys Club and Inverness Caledonian Thistle before joining Dundee United in July 2009.