The 23 year-old moves to St. James’ Park for an undisclosed fee and has signed a five-and-a-half-year deal.
Shelvey began his professional career at Charlton Athletic – making his league debut aged just 16 – before moves to Liverpool and Swansea saw him amass 126 Premier League appearances and earn six full international caps to date.
“I’m very excited to be here. I’m so glad that it’s finally done,” said Shelvey.
“I drove up through the night to be here so it’s been a manic 24 hours but it’s all been worth it to come here and play for this great club.”
Newcastle United head coach, Steve McClaren, added: “I’m delighted to welcome Jonjo to Newcastle United.
“He has great experience for a young English central midfielder and he is a current England international so I’m certain he will be a great addition to the squad.
“He is a player we have admired for some time and we’re very pleased that we’ve now been able to bring him here.”