His first act in his new post was to head to Scotstoun on Friday night and oversee one of the more encouraging performances from Glasgow Warriors and Edinburgh, with plenty of entertainment in a match where both sides had their moments and gutsy passion was never in short supply.
Anybody who thinks these derby games don't matter enough to the players should have seen the bloodied face of Al Kellock, the Glasgow captain and former Scotland figurehead, as he sat and analysed the game – his exhaustion was clear after 80 minutes running on a soft, muddied pitch, that standing was a penance too far – or the mixture of fury and desolation on the face of his Edinburgh counterpart, Greig Laidlaw, as he promised there would be no repeat of the shortcomings that lead to their 23-14 defeat, when the sides meet again on Saturday.
That is the real delight of these historic, inter-city matches, the silverware for which is decided on an overall points tally. After smashing lumps out of each other at Scotstoun, they have eight days to patch up the wounds, move 40 miles east to Murrayfield and do it all again on the more open expanse of the national stadium, with the 1872 Cup trophy being handed to the overall winner.
Strangely, both teams go into that match feeling they did enough to have a realistic chance. For Glasgow, it was the first half and the "grit" they demonstrated in the final quarter when they knuckled down, switched to a more basic game plan and rode out the final action with enough poise to deny Edinburgh a losing bonus point.
For Edinburgh, the expectation mainly comes from the way that, after being way off the pace in the first half, they recovered enough to win the second – giving them encouraging momentum going into the return match.
"There was enough there," maintained Laidlaw. "I was very disappointed in the first half, though. We had to make the one-on-one tackles, too many of them were missed; we must stop getting blocked out of the line, we let them get away with murder at times and that will not be happening next time.
"Nine points is not too much to catch up and I was pleased with the way we played in the second half, apart from a couple of little inaccuracies. We will take that, sharpen up on the first half and move into the next game."
Any criticism of the Edinburgh team as a whole has to exclude their captain, who more than justified all those who have suggested that after his experiment with playing fly-half, he would be well advised to move back to his more natural position at scrum-half. Johnson must have been impressed by what he saw.
What must have given him more of a headache was that the individual game-changers for Glasgow were not the Scots in the team. The pack was outstanding as a unit, but the flair came from Niko Matawalu, the Fijian scrum-half, and DTH van der Merwe, the Canadian wing who was delighted to be back scoring tries after an injury lay-off and a four-match drought.
"I can't remember the last time I scored," he admitted after his first-half try double set the platform for the win. "It is great to be back playing and scoring. With all the competition we have here now and four games without scoring, you fear you will lose your spot in the team. I was thankful the coaches showed faith in me and happy it paid off."
Nipping at the heels of a dominant pack, Matawalu was a continual threat, his perfectly placed chip kick setting up van der Merwe's second score. The partnership also nearly created a try for the scum-half had he not run a couple of feet too far so that the wing's off-load missed him and went to Kellock instead.
Johnson is naturally denied the services of both players in Scotland's dark blue, though he can take encouragement from the way the Glasgow forwards took on their opponents, dominating the breakdown and reaping the rewards despite neither side achieving much ascendancy in the set-piece.
"There are things to improve on," was the verdict from Kellock. "You would not want to have come into this match with the short turn round that we had and think you had cracked it. I feel we have done the first job; we have gained four points in the league, which was massively important.
"The next game will be an entirely different challenge, but I am looking forward to my Christmas a lot more than I would have been if we had not squeezed that one out. I'm sure my wife and wee girl are delighted too that they are not going to have some grump with them for the next few days."