When the Leeds captain received his first call-up for the senior squad under Gordon Strachan back in 2016 - ironically against Denmark - he was left on the bench, and would have to wait another three years before finally earning his first cap.
Fast forward five years, and Cooper is set to start in the heart of the back three at Hampden Park tonight after a solid performance in the 2-0 win over Moldova on Friday that secured Scotland' s place in the World Cup play-offs.
Both he and the country have come a long way since that international introduction. Cooper now has 11 caps to his name and Scotland are looking for a sixth consecutive victory under Steve Clarke on the back of a first appearance at a major finals in 23 years at Euro 2020.
"It feels different now," Cooper admitted. "Success helps that and it breeds confidence throughout the group.
"The boys look forward to coming and it's brilliant. The morale is there and the lads get on great.
"When you come here, it's like a brotherhood. We all buzz off each other and feed off each other's energy.
"That's down to the success. The lads have to give themselves a big pat on the back because we've created that.
"The mentality now when we go into games is a confident one. We know we will turn up in these games."
Fortunately for him, the 30-year-old centre-back is not one of the eight players who are one booking away from a suspension but he insists that those who are walking the tightrope of potentially missing the play-off semi-final will not be affected against the Danes.
"The bookings will be in the back of their heads a bit but we just have to go and put on a good performance and be safe and take care of the yellow cards,” he said.
"You just have to go and blank it out although it's hard not to think about it.
"We all know when the emotions are flying high, it's hard to keep a lid on it sometimes.
"The best way to approach it is to blank it out and play it just like any other game.
"It's a bit of a bizarre rule. There are a lot of games and for it not to be wiped is bizarre.
"It is what it is. Every nation is up against it, we have to deal with it and we will do."
Hampden is sold-out for the second consecutive fixture as Scotland look to get the win that will secure seeded status for the play-offs – and the guarantee of a home semi-final.
"You want to test yourself against the best nations in the world and Denmark are definitely one of them,” Cooper said. "They have had an unbelievable campaign.
"But it's an important game for us. Being seeded is very important to us. The gaffer has made that clear to the group.
"We look to go and get a result because it would be unbelievable to be seeded. We have finished second in the group. We have done what we set out to do.
"But being seeded is definitely on our radar and I think we can do that.”