[1] From North Adelaide, Johnston is seen as a future key-position forward as he is tall, strong in the air and a clever ground player.
[2] Originally from Port Pirie, South Australia, a foot injury during the 2009 season saw Johnston failing to make his debut.
[3] In round 10 2011 against North Melbourne, Johnston finally made his senior debut for the Swans.
In October 2011 Johnston was traded back to his home state to the Adelaide in exchange for Tony Armstrong.
[6] Due to a number of injuries his career was cut short, and was delisted by Adelaide at the conclusion of the 2014 AFL season.