Sam Johnstone, who has been on Manchester United’s books for 13 years, has yet to appear for the Red Devil in the Premier League.
United manager Jose Mourinho feels the 23-year-old is developing quickly and is seen as one for the future.
“Sam is a goalkeeper with great potential,” said Mourinho. “He is a very professional young man with a great attitude to the game.
“He has progressed immensely even during my short time at the club. I am delighted he has committed his future to Manchester United.”
Johnstone, who has been on loan to various clubs, including Walsall, Doncaster Rovers and Preston North End, thinks training with David de Gea and Sergio Romero will further improve his skills.
“I am delighted to have signed a new contract,” Johnstone said. “I have been with the club since I was 10 years old and have grown up here.
“The last 13 years have flown by and I have enjoyed every moment of my time here so far.
“I am working with world-class goalkeepers every day and now I am going to use all that experience to push myself and show the manager what I can do.”