The talented defender has joined the Magpies in the Championship.
The 20-year-old is a highly regarded prospect but failed to make the jump into the first-team at Parkhead and despite this he has no hard feelings towards his boyhood club.
“I’ll never criticise Celtic – you won’t hear any sour grapes from me,” said Findlay, in quotes published by the Daily Record.
“It didn’t work out for me at that club. Maybe it was just the wrong time for me when managers weren’t prepared to give me a chance.
“But I learnt a lot and I have no regrets about my time there. I wouldn’t be in the position I am now if it wasn’t for Celtic. They’ve trained me for 10 years and given me unbelievable experiences."
Findlay joins the Rafa Benitez revolution on Tyneside as the Spaniard looks to build a squad capable of returning to the Premier League at the first time of asking, and he will hope to force his way into the first-team picture sooner rather than later.
Celtic’s decision to let the youngster go is a strange one considering his steady progress in recent seasons and the lack of centre-back options currently at the club.
Findlay enjoyed successful loan spells at Greenock Morton, Dumbarton and Kilmarnock over the past two years and has progressed through the youth ranks for the Scottish national team.
The Hoops meanwhile are facing something of a crisis in central defence with Efe Ambrose looking unfit for purpose and Erik Sviatchenko the only other senior option currently available, leading to some suggestions that Findlay may have been a useful figure to keep around.