A forward, he spent three seasons at Melbourne and although he did not kick a goal in his last five games of the 1978 VFL season, his 31 goals for the year was just two short of winning the club's leading goal-kicker award.
[1] He switched allegiances to Geelong for the 1979 season and performed credibly, although he became known for his inaccuracy in front of goal.
Johnston is perhaps best remembered for his role in the 1981 Preliminary Final, against Collingwood, due to the circumstances surrounding his late inclusion.
As a result of a communication breakdown, former St Kilda player Garry Sidebottom was not informed of his recall into the preliminary final team and was asleep at his home in Lara as the team bus passed through.
Johnston had initially been named as an emergency and travelled to VFL Park by car with two other players.