Goalscorer, potential Player of the Year - and theory buster.
Not much in football can boast almost universal agreement. But the belief that doing your transfer business in the January window is so much tougher than buying and selling in the summer gets the thumbs-up from nearly every manager and agent.
Even Celtic boss Neil Lennon and chief executive Peter Lawwell are in accord on this one.
But they consider their hand is being forced, due to the timing of the opening Champions League qualifiers.
So, it is reassuring to both men that Commons is living proof you can land a good 'un in the mid-season window - and that he can hit the ground running.
His £300,000 transfer from Derby three years ago next week was marked by a goal within 24 hours from the man born in Mansfield.
He had already been scoring for fun with the Championship club, and had also got off the mark for Scotland.
Commons' positive experience and instant return is something of an exception, however, as the litany of players who have made their move in January but lacked the fitness or the form to make any real contribution for several weeks - or, in many cases, ever - testifies.
Even Mikael Lustig - another key component of this Hoops team - struggled for the remainder of the season when he was brought in from Rosenborg in January, 2012.
The fact the Swede had already completed a calendar year season with the Norwegian club prior to his move across the North Sea was a major factor in his delayed assimilation.
Now it is the new Bhoys, Stefan Johansen and Holmbert Fridjonsson, who are dealing with the issue of recovering from a full season - with Stromsgodset and Fram Reykjavik, respectively - and kicking on again in a Celtic side only halfway through their programme.
Commons is on hand to offer the benefit of his experience to the new arrivals, and any others recruited in the next few days.
He said: "When I came through the door, I had been in the Scotland squad a few times.
"I also knew the manager very well, and there were players here at the club, like Charlie Mulgrew, James Forrest and Scott Brown, who I already knew.
"So, it wasn't a massive difference for me in terms of changing dressing rooms.
"The Championship at the time was also of a good standard and I had been playing at a decent level.
"I could come in here and just continue to play my football.
"I had scored quite a few goals in the first half of the season with Derby, so I was confident when I made the move, anyway."
In fact, Commons flew into Glasgow on a high, the then 27-year-old having enjoyed the most productive first half of any season in his career.
His 13 goals for the Midlands club had catapulted him into Craig Levein's Scotland team. And his first-ever goal for his country, against the Faroe Islands in November, 2010, confirmed he could carry this striking form with him.
Adding 15 goals in his first four months as a Celt saw his tally for the season rise to 29.
Now, having banged home 19 goals this term, the question is, can he better that total?
"It is a target I would probably look at," is his considered reply to that one.
"But, while people keep reminding me how many goals I've been scoring, I'm trying to forget and just concentrate on playing decent football.
"I just seem to be in the right place at the right time at the minute, and getting the scruffy goals rather than the world-class ones."
His manager does not care how he finds the net, so long as he continues to do so.
While the search for a proven goalscorer willing to come to the club, and within Celtic's price range, picks up pace ahead of the window closure on January 31, the onus is on Commons to keep providing the finish to the chances so many in the side are capable of providing.
Lennon can see no reason why the attacking midfielder cannot hit the 30-goal mark, something close pal Gary Hooper managed only once in his three seasons as the Hoops main striker before his sale to Norwich last summer.
However, Commons has been around the block often enough to know that looking too far ahead leaves you vulnerable to tripping over something right in front of you.
While the 30-year-old is delighted to be riding the crest of this form wave, he needs no reminding you can come crashing down very quickly.
Last season he was going like a train in the first half of the campaign, but struggled to maintain that form after the club turned for home in pursuit of the league and Scottish Cup double.
He is determined there will be no drop off this time around and said: "I don't want to have any blips.
"I'm looking to try and maintain my goalscoring form.
"And, if I am not scoring, then I want to be the one creating goals for others.
"There is a big drive from me for this, and I want to be a big part of what is going to be happening next year as well."
Commons acknowledges that, while his mind must be kept on the moment, it is incumbent on the men who run the club to put in place their plans for next season.
And, even though the current form of the team confirms they are not in desperate need of help to carry them towards a third consecutive championship and back-to-back doubles, those crucial July qualifiers are already looming large.
"We are definitely looking long-term," said Commons, referring to the fact the club are cranking up their attempts to add more quality additions before the window closes.
"We've got half an eye on next season, and the Champions League qualifiers that just seem to pop up from nowhere.
"So, it's important we get players in now of good quality who are going to give us that extra edge in the top club competition in the world.
"You could kind of see that, that we were just lacking that cutting edge this term.
"So, we need to invest."