Four tries in six appearances for the Ireland Under-20s, 16 tries in 52 outings for Ulster and five touchdowns in two non-cap internationals for Ireland this year.
Gilroy also has a welcome habit of scoring on his debut for various teams, including a hat-trick for the Dungannon seconds and a memorable brace for Ulster against the Cardiff Blues in November 2010.
His chances this season at Ravenhill have been slightly curtailed due to Tommy Bowe's return to his native province, and it was actually Bowe who presented Gilroy with his jersey for the GUINNESS Series finale against Argentina.
As he drew breath after a momentous day for him personally, the young winger admitted: "I can't really pick one (highlight). Just everything, from Tommy (Bowe) presenting me with my jersey at the Shelbourne (Hotel) before we came. I didn't know that was going to happen and it did.
"The drive to the stadium and all the fans, the whole day was amazing. The anthem. If I had to say one, probably just the feeling after I scored and everyone came around me, I'll never forget that."
There was a rush of players to congratulate Gilroy after he had danced through the Argentinian defence, having been fed by Jonathan Sexton on the 22.
As the Opta stats reveal, the Belfast-born flyer had a first cap to remember. He had 12 runs covering 111 metres and four breaks, to go along with that deftly-taken 11th minute score.
Two missed tackles and a kick that went out on the full will gnaw at him, but the Dungannon clubman had another otherwise dream first Test at the Aviva Stadium.
"I was eager to take my chance because who knows when it will come again. Past players said your first cap is special, just enjoy it," he remarked.
"They said it just flies by and it does, but there are also moments I won't forget. It felt surreal. I couldn't believe I was there. Once you've had a taste of it you want more."
Admittedly gripped by nerves beforehand, Gilroy revealed that messages of support from family and friends settled him down. The manner in which he slotted into the Irish side will give him confidence for more testing days ahead.
"Declan (Kidney) spoke to me after the game and congratulated me. He told me to keep my feet on ground. He was happy with me.
And what was his take on the try and the swarm of congratulations he received from his new international colleagues? It was a moment he will most definitely cherish.
"Being surrounded by the whole team just after scoring that try is a moment I'll never forget. That's the sort of moment you think about when you get into the team. It was euphoria, it was amazing.
"For my try I saw a gap and thought, 'it's on'. The rest just happened...I couldn't really control it. I started stepping and I was over."
A player who made his own international bow some 13 years ago, Gordon D'Arcy, was delighted to see Gilroy deliver on the biggest stage.
The experienced centre, the most-capped of Ireland's starting backs on Saturday afternoon with 70 caps, said: "Just talking to Craig, I said you're here because you do what you do really well.
"And I told him to go out and do that today. He did it unbelievably well. He's so hard to tackle, has the ability to shift on both feet.
"When he's hit, he can spin and keep going. And he chased every ball. Defensively, he was solid. He had an exceptional game for a first cap."
D'Arcy was particularly effective himself against the South Americans, putting in nine tackles, missing none, and covering 42 metres on his nine runs with the ball.
The 32-year-old is enjoying the current influx of youth in the Ireland set-up as competition for places hots up in advance of the RBS 6 Nations Championship.
"We're definitely on the start of a really exciting group of players who are bringing their own unique brand to the Irish jersey," he added.
"I think you can see a definitive Irish way of playing that's kind of different from all the provinces. The management have done a really good job in basing a game-plan around the strengths of the players.
"The younger guys, they'll have learned a lot from what they've seen. From the South Africa game, having to be mentally tough in a tough environment.
"And then today how pressure, pressure and pressure can create opportunities. Two different learning curves but both very important and hopefully they can combine for us going into the Six Nations."