The Blues went down by 15-points, but Johnson said they put in a competitive performance.
"I think that we were always in the game,” Johnson said.
"We started off a bit slow but we were in it until the end, so it’s a big credit to the boys.
"It was a bit unlucky to not get the win, but it was good to finally put on the boots for the Blues."
The 18-year-old, who was recruited to Carlton through last year's rookie draft, was upgraded to Carlton's primary list last month when Heath Scotland hung up his boots.
Johnson said being told late last week that he'd made senior selection came as a shock.
"I think that I found out on Friday afternoon, " Johnson said.
"It was a bit of a surprise as I was expecting to play in the VFL – but then I got the call–up – so I took it!"
Starting the game as a substitute, Johnson had an anxious wait until his turn finally came when Dennis Armfield came off in the third quarter.
Johnson said the time spent on the interchange bench was nerve-racking.
"I just tried to stay relaxed as much as possible,” Johnson said.
"I got around the boys as much as I could then went through my warm-ups and started to get prepared."
Once on the ground the debutant didn't disappoint, managing four kicks in his seven disposals.
Most footballers will always remember their first game and Johnson is no exception.
"It's a memory that will probably last me a lifetime," Johnson said.
"It's the biggest crowd that I've ever played in front of."
