Injury and form lapses caused Johnston to miss a place in St. George's 1985 Grand Final side which went down 6–7 to the Canterbury-Bankstown Bulldogs, although he did play in the reserve grade grand final win against Canberra.
Injuries and poor form caused Johnston to be omitted from St. George's 1985 Grand Final team, leading to their defeat by the Canterbury-Bankstown Bulldogs. Despite this, he did play in the reserve grade grand final against Canberra.