Ireland cap number 28 was a long time coming for Kearney, who suffered cartilage and ligament damage in his left knee against New Zealand last November.
A satisfying 80-minute run-out against Scotland on Saturday was the reward for his patience and the collective care taken with his recovery.
After the match Kearney explained: "Brian has been been fantastic over the last nine months. When you're injured you're out in the cold a little bit at times.
"You only have your rehabilitator to whinge down the phone to and throw your strops with, and he was brilliant.
"Between himself and Stephen Smith back at Leinster, who was my rehabilitator there, I was really lucky to have both of them and I couldn't appreciate their work, their time and effort any more.
"(Giving Brian my jersey) was just a small gesture. I just wanted him to know how much I appreciated everything he has done."
Having come through the Murrayfield encounter unscathed, Kearney was just delighted to get his first game out of the way considering the prolonged build-up to it.
"It's a huge relief to be playing again. I'd been nervous all week and I don't usually get nerves beforehand.
"I came across some big obstacles. The result wasn't what we wanted but from a personal perspective it was good to get through it.
"I felt really good at times, but was blowing at other times. All in all I was happy and felt pretty comfortable."
The Louth native is keen to play in next weekend's clash with France in Bordeaux, but will leave that decision up to the coaching staff.
With his first Rugby World Cup experience just weeks away, it is clear that he is itching to regain the sort of form that saw him star on the tour Down Under in 2008 and during the Grand Slam run in 2009.
"I've come back from injury before where you try to do something magical, but my main focus was to do the basics right and make as few errors as possible.
"I was pleased with the way it went, but if I'd had a shocker I wasn't going to judge myself too much.
"Likewise if I had a stormer I wasn't going to get over excited either. I don't know if I'll be playing every week, but I'd love to play every week."
Declan Kidney admitted afterwards that Kearney was not due to finish the game. But according to the head coach, who said the full-back is 'motoring in training', he will be all the better for getting a full 80 minutes into his legs.
"When I saw (one of our replacements) Felix Jones on the line I wasn't happy to be going off, but I thought maybe that was for me," added the 25-year-old. Instead, debutant Jones came on for Kearney's Leinster colleague Luke Fitzgerald.
"During the week I'd prepared for 60 or 70 minutes, maybe a little foolishly. Then I'd got cramp towards the end for the Scottish try.
"I was a little bit surprised I got through the full 80 and was given the full 80. But the knee feels brilliant, which for me was the most important thing.
"There were a couple of tackles and contact situations where I thought, 'it's nice to be back'. You appreciate those collisions again in a strange sort of way."
Kearney's movement was impressive as he twice raced up to tackle Chris Paterson after the Scotland full-back had fielded high balls. He was also well-positioned to snuff out a try-scoring chance for winger Nikki Walker early on.
His passing was crisp and a jinking run into the Scottish half saw him break away, only to be called back for a forward pass earlier in the move.
There was also a noteworthy catch of an up-and-under in the second period, an aspect of his game that the 2009 Lion is renowned for on the world stage.
Giving his assessment of the game, Kearney admitted: "It was tough and physical out there. We did a huge amount of defending and we had very little ball to play with. We attacked very little.
"In the first half all we could put together in Scotland's half was seven or eight minutes. It's difficult to win games when you have such little possession but we were hanging in there. It was looking good until the try at the end."