This 38-year-old qualified teacher, unknown in Glasgow at breakfast time yesterday and a man hundreds of thousands had an opinion on by lunch, walks out of the tunnel and strolls down towards where the bulk of the Stromsgodset fans gather. In front of them he heavily kicks an advertising board a few times.
It is a gesture to whip them up, to get the supporters going. It is three years since the club last lost a home league game.
By Norwegian standards kicking the advertising might pass for delivering "the thunder". But in no real sense will Deila ever be mistaken for Neil Lennon, the man he is close to following into the Parkhead manager's office.
Their backgrounds, characters and even their credentials could not be more different. Deila is far more experienced in management than Lennon was when he got the job in 2010 but there will be plenty of Celtic supporters who worry that they are about to appoint an innocent who does not realise what he's letting himself in for. Lennon was steeped in Celtic, in Glasgow, in the west of Scotland, in the Old Firm. Deila may feel he is adequately prepared for what might come his way but he has no grounding in the size, intensity and relentlessness of the demands which come with managing Celtic. The gamble, if they give him the job, is that he can handle it.
Within minutes of his name being circulated yesterday a picture was doing the rounds of Deila looking a little loopy. He had stripped down to the underpants, hurling his discarded clothes into the fans after a game in 2009. Eccentricity is not something of which he makes a habit: Stromsgodset had just won an end-of-season game to save themselves from relegation.
Usually he is sober and down-to-earth. "Ronny is an honest guy and he works hard," said Bryan King, the former Millwall and Coventry City goalkeeper who lives in Norway as Everton's scout in Scandinavia.
He knows Deila. "He's a family guy. Whether the language would be a problem I don't know . . . it's hard enough to understand you jocks as an Englishman. He's not one of those who thinks he's on another level. He's a fans' man and he works hard. Plus he's a good guy.
"He doesn't forget where he's come from. I wouldn't have imagined Celtic would have been fishing for him apart from him being maybe a bit of a cheap option. But could he handle it? I'm sure he could, even though it's a really big job."
In 2008 Deila was only 32 when he was promoted from assistant coach to manager. Stromsgodset were committed to shrewd player recruitment, youth development, a modest wage structure and low transfer funds. Deila was not just prepared to go along with that, he was an enthusiastic architect of the model. Making the whole thing palatable to the supporters - their average crowd is just under 6000 - was the fact Deila was committed to attacking football, often playing a 4-3-3 formation. The team began an almost uninterrupted rise.
Stromsgodset have a very modest history and are not one of Norway's bigger clubs yet their last six league finishes have been 11th, 12th, 7th, 8th, 2nd and 1st. Winning the title in 2013 was remarkable: the club had not done so since 1970 (they had won the Norwegian Cup in 2010 for the first time since 1991). This season they are second, five points behind Molde with 11 games played before the Tippeligaen took its break until after the World Cup finals.
His strengths are team-building and man-management. He is said to have a warm, engaging manner which eventually draws a group of players around him and into a coherent, strong unit. His players are challenged and encouraged, and setbacks are tolerated if they have tried and failed to implement something at the first attempt.
It is a progressive, modern approach to management. His admirers liken him to a Norwegian Brendan Rodgers or Juergen Klopp, the Borussia Dortmund coach he visited and spent time with last year.
What team-building needs is time, of course. Getting that at a small Tippeligaen club without a demanding fanbase, and getting that at Celtic, are two different matters. Another issue Deila will have to be cute enough to deal with is the possibility of a "show us your medals" attitude among the players he will inherit. His modest playing career and successful managerial spell were both spent entirely within Norway. Transplanting a winning manager from one environment and hoping he will be similarly successful in another one is a tried-and-tested approach which has been pock-marked by numerous failures.
If Celtic were aware of Deila before, then he impressed them even more during the negotiations to take Stefan Johansen from Stromsgodset to Parkhead in January.
The 23-year-old has been an impressive performer in his opening months at the club and he now has a crucial role in garnering dressing room support for Deila.
Johansen is popular with the other players and if he says Deila is a good man, and a manager who deserves their respect, it will help buy him precious time.
There is little media attention on Stromsgodset, even by Norwegian standards. In Glasgow he will be public property. That will be new to him and so will be the expectation that his team must win every game and be competitive in Europe.
Deila has had only eight UEFA games as manager, losing six of them, albeit that Aston Villa and Atletico Madrid were among his four opponents. Stromsgodset are about to compete in the Champions League qualifiers for the first time. They enter, unseeded, in the second qualifying round. Celtic are seeded, so the clubs could draw each other.
In going for Deila, Celtic are being imaginative and forward-thinking. He is a young, progressive coach who chimes with how the club would like to see itself.
It is a good time to take the job but not a single fan, nor any Celtic director, knows whether Deila will handle it because that is impossible to predict. This, after all, is a position which saw Lennon rise and John Barnes and Tony Mowbray sink without trace.
Deila, an unknown 24 hours ago, is close to becoming the most compelling figure in Scottish football.