The teenage winger, who primarily plays on the right flank, agreed terms with the Magpies after turning 17 and has been involved with United's under-18s side this term after his recovery from a long-term hamstring injury.
Pinnington, who joined Newcastle's Academy from Luton Town as a 14-year-old, was delighted to sign his first pro deal and believes his three-year spell with the Magpies played a big factor in his decision to commit his future further at St. James' Park.
"It feels great to sign my first professional contract," the Harpenden-born youngster told newcastleunited.com. "It's been something I've wanted to do since I've been really young so I'm very happy to sign it, especially with Newcastle.
"The club has got great staff, facilities and I like the journey that the club is going on at the moment. I've been here since 14 and they've helped me in so many ways, especially after moving up away from home so I didn't want to go anywhere else."
After making a difficult choice to move hundreds of miles from Hertfordshire as a 14-year-old, Pinnington believes the move has paid off and has his sights set on a successful 2025/26 campaign, with Newcastle's under-18s side currently occupying second place in the Under-18 Premier League North.
The teenage winger, who cites Neymar and Lionel Messi as his footballing idols, is also hopeful he can follow in the footsteps of Academy graduates such as Lewis Miley, Sean Longstaff and Elliot Anderson in featuring for the club at senior level.
He added: "Making the decision to join Newcastle was 100 per cent worth it! I can't speak on behalf of every team but Newcastle has helped me progress both as a player and person and they are the reason why I'm doing as well as I am right now.
"For this season, I want to focus on doing the best I can in every game and training session to see where that can take me.
"I'm aiming to play for the first-team at St. James' Park - that's an ambition in the long-term future - and something I really want to do."
Academy director Steve Harper added: “Signing his first professional contract is an important milestone for Sammy and one he fully deserves after the progress he has made throughout his time in the Academy.
“Sammy has approached his development with real focus and professionalism, reflecting the standards we look for in young players preparing for the next step in their career.
“We look forward to supporting him as he continues to grow and challenge himself within a demanding and supportive setting.”
