From Greek heritage, Karnezis is close to parents Con and Sandra and found his initial time away from home difficult.
But the 19-year-old quickly found his feet both off and on the field and was a revelation for the Lions in 2011.
He played the final 11 games of the season, kicked 17 goals (including multiples in seven matches) and won the club's Rookie of the Year award.
This pre-season, Karnezis has hit the ground running, hell-bent on adding to his light frame and underdeveloped aerobic tank.
When taken at No. 25 in the 2010 NAB AFL Draft, the 191cm Karnezis tipped the scales at just 78kg.
After a full year in the gym, he now weighs 87kg. It's a remarkable gain in a short time.
"The pre-season is a big thing for me and I'm trying to hit the gym hard and add a couple of kilos," Karnezis said after a weights session on Thursday morning.
"I'm even a bit surprised at myself, it's going really well. The improvements I've seen from last year are incredible."
There's no doubting Karnezis' talent. He played predominantly as the third tall forward last season and has strong hands overhead, reads the play well and is good below his knees.
But Karnezis realised he had to step things up if he wanted to seriously compete at the top level.
"I felt in a lot of one-on-one contests I got caught out physically," he said.
"I played some experienced defenders from Hawthorn and Geelong and it was pretty obvious I was a bit underweight and getting chucked around and I had to find other ways to exploit my defender.
"This year it's a bit different, I'm trying to put that weight on so I can match up physically one-on-one."
Ironically, a season-ending knee injury to his housemate Brent Staker opens the door for Karnezis to cement a spot in the Lions' forward line next season.
Karnezis will play alongside experienced captain Jonathan Brown, and said you could not put a price on learning from one of the game's champions.
"His knowledge of the game as a forward is incredible," Karnezis said of Brown.
"He's helped us with techniques and leading patterns and it gives you way more confidence and it's just amazing having him out there."
The past 12 months has been a whirlwind for Karnezis. He's overcome homesickness, bulked up his light frame, improved his running capacity and now hopes to be an integral member of a Lions team looking to climb from the basement in 2012.
Michael Whiting covers Brisbane Lions news for AFL.com.au. Follow him on Twitter: @mike_whiting
