The 17-year-old defender impressed on a recent trial with the Magpies and has agreed terms on a three-and-a-half-year contract.
The Switzerland U19 international will go into the club's development squad after completing his move from Servette.
"Today is a big day for me. I've always wanted to sign for a club in the Premier League and Newcastle is one of the biggest there is," he said
"I want to finish my development here with the reserves before one day training with the first team and hopefully breaking into the first team."
Newcastle reserves manager Willie Donachie said: "Kevin is strong, confident, skilful and a very good prospect.
"He still has a lot to do as he is only 17, but I saw him playing for Switzerland U19s against Scotland and he did really well.
"He can play central defence or right-back and if he keeps working hard then he could have a great future in the game."