The athletic 18-year-old has enjoyed two short stints with the Blues and has impressed while training with the senior group.
Byrne, who stands a lean 187cm, was spotted by Carlton scouts at a camp in Limerick two years ago.
Under the Blues' guidance, he has improved his skills considerably.
From Dundolk in County Louth, Byrne is a member of the Ireland squad that will host the Indigenous All-Stars in the International Rules Series in October.
"In his game he's a very good player," Carlton recruiting manager Wayne Hughes told carltonfc.com.au.
"He's got all the athletic qualities that you look for."
Byrne joins fellow countryman Zach Tuohy, who will play his 50th game this weekend, at Carlton.
Asked to compare the duo, Blues football operations manager Andrew McKay said Byrne was taller but was more finely built than Tuohy.
"Ciaran's a good athlete and a good running player, in keeping with all Gaelic footballers," he said.
McKay expected Tuohy's example to have a positive effect on Byrne.
"It's been good for Ciaran to see what can be achieved when you put your mind to it," he said.
McKay said Byrne, like most budding AFL players from non-traditional football backgrounds, was a medium to long-term prospect.
"It's all well and good to kick and catch, but you also need to understand where the ball's going to go and to read the play a bit … and he's never played the game before," he said.
Byrne will join the Blues on their altitude camp in Arizona in December, before returning to Ireland for Christmas. He will rejoin pre-season training in January.
Tuohy is excited by the prospect of having another Irishman at Visy Park and also understands his responsibilities.
"I've always said I'll always encourage any Irish player to come over and give it a go," he said. "It's not a holiday – it is hard work.
"You need to be determined and it has to be what you want to do."
