In his first year as a manager Johnston could do no wrong, worshipped deliriously by Queen of the South supporters after leading them to a double of the second division title and the Ramsdens Cup. His stock had never been higher and Kilmarnock were quick to capitalise, bringing their former player back to Rugby Park last summer to replace Kenny Shiels.
His second season in management has not been quite as agreeable. It took until mid-October before the team finally recorded a victory, and they were knocked out both cup competitions at the first hurdle. After a purple patch, Kilmarnock have suffered a relapse in recent months to the point where they need to take at least a draw from this afternoon's match away to Hibernian to be sure of avoiding the play-offs.
With Johnston on the receiving end of some cutting and vitriolic abuse from supporters who question his ability, he could be surely forgiven for harking back dreamily to those days at Palmerston when it all seemed a lot easier and a lot more fun.
That is not in his make-up, however. He concedes this season has been a real test of spirit and character but that he is not one to shirk from the challenge. Attaining a positive result at Easter Road is all he is focusing on for now.
"I knew it was going to be really tough when I came in," he said. "The budget had been cut and we'd lost a lot of experienced players, who had left in the summer. The timing was difficult as well: I came in at the very end, just before pre-season so I always knew it was going to be a tough test. And it proved to be that way.
"You learn every season. You learn every week. Hopefully, it makes you a better all-round manager, dealing with this kind of pressure as well. I had it as a player as well. You get your highs, you get your lows and it's how you bounce back that matters.
"I'm just the same as I was as a player. I actually came here in my first season and never played well and got a bit of criticism but I went on to do quite well over the years I was here so I suppose that shows a wee bit of determination."
Needing only a draw can sometimes leave a team conflicted about whether to attack or hold on to what you have. Johnston insists his players go to Easter Road in a positive frame of mind. "You can't sit in and defend for 90 minutes and go for a draw. We've got to approach it the same way we approach any game. Obviously, we don't need to throw loads of players forward all the time and go gung-ho. You've got to be balanced at the back and make sure we're organised but we've got to try to get the win as well.
"We need everybody pulling together. It makes a huge difference. You saw that on Wednesday night, the way the crowd really got behind the players. We've got a lot of young players and you can see they respond to that well."
Johnston is also fortunate that he can call upon a player like Kris Boyd, who is expected to shake off an ankle knock to feature this afternoon. This could, in theory, be the final game of Boyd's second spell as a Kilmarnock player but he is concentrating on the bigger picture rather than his own personal circumstances for now. "Looking around the stadium on Wednesday [for the game against St Mirren], there were a lot of nervous people there," said the striker. "It's not nice but the reality is that if this club goes down there will be more cuts.
"This club is at a crossroads where if you go down you could be there for a few seasons. We need to stay in this division and we know that, so we need to put on a performance on Saturday that shows everything that this club is about. We need to work our socks off like we did against St Mirren."