The teenage midfielder joined the Magpies' first team in the Diriyah Season Cup's victory against Al-Hilal in December and was named on the bench for Newcastle United's Premier League match against AFC Bournemouth in February.
Lewis Miley has scored two goals for Newcastle United's under-21s in his last eight Premier League matches and has ten international caps in his name.
He told NUFC: "It's a really good feeling to sign my first professional contract, especially with my boyhood club. It's something that I've dreamt of since I was a kid."
Steve Harper, Academy director, said: "Everyone at the Academy is delighted to see Lewis sign his first professional contract at the club. He’s been with us from a very early age and credit goes to everyone who has played a part to date.
"His hard work, attitude to learning, and training as well as his technical ability has got him to this point. The contract is a fitting reward for his progress."
