The 19-year-old defender has joined the Scottish Premiership champions from Premier League giants Manchester United on a four-year contract.
“I had some options, but it was quite clear when I met the manager at Celtic that I wanted to come here,” the teenager told The Scottish Sun.
“He made it clear what he expects from me and when I saw the ground I wanted to sign. I was sure about things right from the beginning.
“The manager wanted to do things as soon as possible, but the paperwork always takes longer than everybody hopes.
“But he knows what he wants which is good. He knows what he expects from the players so that helps you. I just want to win as many titles as possible, and with Celtic I can do that because it’s a great club.”
Good move for Celtic?
Janko is a talented young player, and the fact that Deila has shown his faith in him suggests that he will get his chances as the 2015-16 season progresses.
The 19-year-old will have a lot of work to do to break into Ronny Deila’s team, but he certainly has the talent and the hunger to do so.
Celtic boss Deila showed last season that he is open to giving young players chances, and Janko will hope to impress the Norwegian during pre-season.
Janko’s versatility will also be a boon to him. The youngster can play both as a right-back and as a right-winger.